Engine lack of power?

Tiny
SUNSHINE86
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  • 2003 DODGE RAM
  • 5.7L
  • 6 CYL
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  • 175,000 MILES
Sounds like it wants to shut off almost. However, if I turn the truck off and start it again it's back to running great! I've changed ignition coils.
Friday, January 31st, 2020 AT 11:49 AM

67 Replies

Tiny
CARADIODOC
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How often does this happen, and for how long?

A good place to start would be to connect a fuel pressure gauge to the test port on the fuel rail on the engine, and hook it under a wiper arm so you can see what happens when the problem occurs. If the fuel pressure drops off significantly, a real good suspect is the strainer on the bottom of the fuel pump housing. I've had these plug up or collapse four times on three vehicles.

check out these guides

https://www.2carpros.com/articles/engine-has-low-power-output

and

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

On all of my vehicles, that strainer was replaceable separately. Cost was $3.00 for the two carbureted engines, and $12.00 for my Grand Caravan with fuel injection. On some models you can only get the new strainer by buying a new fuel pump assembly including the housing. It looks like yours is snapped onto the bottom of the housing, (blue arrow in the photo), but I didn't see a listing online for the strainer separately. You'll have to check at the auto parts stores.
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Friday, January 31st, 2020 AT 4:38 PM
Tiny
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So but the problem isn't every time I go to drive it. It could be just fine for days the I get in and it's droggy blurping spitting. I shut it off turn it on and its like it reset itself. It'll run great after that. So maybe a sensor?
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Saturday, February 1st, 2020 AT 10:23 AM
Tiny
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You're describing exactly the way my '88 Grand Caravan acted. It was one of the hottest days in summer. I drove over three hours, through Minneapolis, then there was a slight sputter when leaving a stop light; just enough to get my attention. 30 miles later the engine died when I let off the accelerator pedal to turn off the highway. It cranked but wouldn't restart until five minutes later. After I visited the shop I went to see, it took me four hours to nurse it back through Minneapolis, then it ran fine at highway speed for another three hours until I started to coast, then it died again.

Next day it was just as hot, and the engine died repeatedly around town, then it was fine for the next six months. Funny thing is, outside temperature should not have played a role with this problem. The solution was a new strainer in the gas tank. $12.00 and didn't have that problem until about 12 years later, then only when dragging a huge tandem axle enclosed trailer that's bigger than the van. While driving with the fuel pressure gauge attached, I could see the fuel pressure gradually drop off from the normal 50 psi to less than 20 psi. It wasn't until it hit 15 psi that the engine would start to sputter.

A clue that I learned by doing that was the fuel pressure would instantly pop back up to normal if I lifted the accelerator pedal for a fraction of a second. Once I pressed it again to keep my speed up, it took from about ten to 20 seconds for the pressure to drop off again. I nursed it home over 50 miles that way. Coincidentally, that happened multiple times over a few days that were very hot in the middle of summer.

This article shows testing the fuel pump:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

but that is not what we're after. It's important to understand that when Chrysler fuel pumps fail, they almost always fail to start up, leaving you sitting in the driveway or parking lot. Once they start up, they rarely quit while you're driving. (GM fuel pumps are just the opposite. They almost always start up, then they quit or slow down while you're driving, leaving you sitting on the side of the road). On Chrysler products, with running problems that develop while you're driving, the fuel pump is way down at the bottom of the list of suspects, but that strainer is up at the top of the list. From your description of the symptoms, the strainer is a far better suspect than any sensor, but we want to verify that first by watching what the fuel pressure does when the problem occurs. This article shows how to connect the gauge. The first time I drove my minivan with the gauge attached, I had it stuck under the right wiper arm. The second time I drove it for a year and a half with the gauge strapped to the radio antenna.

If fuel pressure proves to not be the cause of this problem, we will need a scanner to see what the Engine Computer is seeing and reacting to when the problem occurs. The last thing I want you to do is to replace a lot of random parts. That is the least effective way to solve a problem, and it is often more expensive than getting a professional diagnosis.

You should also read and record the diagnostic fault codes. Chrysler made doing that yourself much easier than any other manufacturer. Cycle the ignition switch from "off" to "run" three times within five seconds without cranking the engine, leave it in "run", then watch the code numbers appear in the odometer display. You can go here:

https://www.2carpros.com/trouble_codes/obd2/p0300

to see the definitions, or I can interpret them for you. Be aware, there are no fault codes for low fuel pressure. There are, however, multiple possible codes for things that resulted from low fuel pressure.
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Saturday, February 1st, 2020 AT 5:55 PM
Tiny
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Okay, so now today. Code p0700 and p0300 are on and truck is in limp mode. Help?
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Monday, February 3rd, 2020 AT 2:45 PM
Tiny
CARADIODOC
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Code 300 means "random cylinder misfire". That can be caused by low fuel pressure. Code 700 means there's one or more diagnostic fault codes in the Transmission Computer. You'll need a scanner that can access that computer to read those codes. Cycling the ignition switch to read the codes, and most simple fault code readers, can only read codes in the Engine Computer.

P0300 - Random/Multiple Cylinder Misfire Detected
P0700 - Transmission Control System Malfunction
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Monday, February 3rd, 2020 AT 3:02 PM
Tiny
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Lets talk spark plugs. Is Champion a good kind? And what should I gap them at?
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Friday, February 7th, 2020 AT 8:54 PM
Tiny
CARADIODOC
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Nothing you've said so far points to a spark-related problem. If you were my customer, it would be irresponsible for me to sell you spark plugs in the hopes that would solve something. We already get accused all the time of trying to sell unneeded parts and services, but that's what you want to do. There's about a 95 percent chance this is fuel pressure-related, so that should be verified or ruled out before spending money on the less-likely suspects.

The best spark plugs are the ones that came originally in the engine. Usually that will be Champions in a Chrysler engine, but even they have non-original designs. Unless you know from previous experience that a certain spark plug works okay, stay away from anything considered to be an "upgrade". The ones that cause the most problems are split-fire designs that have multiple electrodes. They work fine in the engines that were designed to benefit from using them, but on many others those will lead to misfires or running problems. I've read too often where new problems developed when an engine was tuned up and the new, more expensive spark plugs were the cause of those problems. Switching back to the original part numbers almost always solved the problems.

Spark plugs play a big role in emissions. As such, if there was something better, the engineers would have used them on the assembly line, and that would be what they specify to use for replacements.

The original spark plug number is RE14MCC4 (Champion). The gap is listed as.044".
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Saturday, February 8th, 2020 AT 2:55 PM
Tiny
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Well so far so good. Crank position sensor. All 16 spark plugs. New coils. And it's running almost at 100%. The only problem now is after the third shift she gets a lol droggy but into fourth can't notice it. I guess it's all the little things that add up.
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Sunday, February 9th, 2020 AT 4:50 PM
Tiny
CARADIODOC
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You're still describing the way my Caravan acted. The fuel strainer caused problems two days in a row, then I did a tune-up a week later even though it was running okay. It wasn't until six months later that the problem started to act up again every once in a while. I'll keep my fingers crossed for you, but if this was my customer's truck, I would not have the confidence to tell them the problem was solved.
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Monday, February 10th, 2020 AT 3:13 PM
Tiny
SUNSHINE86
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  • 2003 DODGE RAM
  • 5.7L
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First start up truck will idle rough and rpm's will fluctuate. When going to drive it it will chug as if its lacking gas when you accelerate and let off gas pedal. Rpm's will rapidly drop and rise. Sometimes causing truck to shut off. But if I turn key off and back on it's back to normal and running good for remainder of the day. If it sits again for a little while it happens all over again. I have changed spark plugs, Ignition coils, position sensor, sort of cleaned the intake manifold and it has got a new belt, new battery. I have checked into fuel filter however for this year and model can't just buy filter have to buy whole assembly kit which costs $350.00. O2 sensors? Catalytic converter? These are the next things I will be checking. If there is anyone who has this problem or any mechanics that have resolved this problem please I'm open to any ideas.
I do understand that this is a common problem in a 5.7 hemi. But I haven't read a solution yet.
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
JACOBANDNICKOLAS
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Hi,

Based on what you said, there could be many different issues. Have you checked for engine vacuum leaks? Have you confirmed that the fuel pressure is with spec?

I suspect the check engine light is staying on when the engine is running. Have you had the computer scanned? If you haven't, that is where you need to start. Often times a parts store will do it free of charge. If this is the case, have that done and let me know the exact codes that are found. If you happen to have a scanner that can provide live data, please let me know what both the short and long term fuel trims are.

Let me know if any of these things have already been done. Once I start eliminating things, it will get easier.

Let me know.

Joe
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
SUNSHINE86
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The check engine light does not stay on and scanner reads no codes!
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
SUNSHINE86
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That's why I tried that trick where you turn ignition to start and back off 3 times it'll show on dash the check engine light will flash for hidden codes or something like that so I tried it. It flashes 10 times but scanner says no codes.
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
JACOBANDNICKOLAS
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Hi,

That process should show a P code in the odometer. Does anything show there? Could it be a P0110? That is an intake air temperature sensor issue. That can definitely cause a drivability issue. However, I would think it should show on the scanner and you said it didn't. Do you have access to a live data scanner?
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
SUNSHINE86
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I do not. But I'm waiting on a car shop they said that they would run a scanner on the truck however they just sent it in to get updated.
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
GRANT19
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  • 2003 DODGE RAM
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 99,000 MILES
I was driving down the road then I heard a clunk and my check engine light came on. I lost all power to my 03 Dodge Ram 1500 6 Cylinder truck. Now the truck runs like normal until it gets kinda hot. Then it wont go above 2800 rpm, has no power, makes weird noises, and back fires really bad. Any ideas?
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
JDL
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How long since a tune-up? Check applicable trouble codes. Do a compression test. Use a gage and check fuel pressure, that is part of tune-up.
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Do you know what they are updating? Or, has the work already been done? If so, has it taken care of the issue?

Let me know.
Joe
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
GRANT19
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Not sure just bought it from a buy here pay here place. I checked the fuel pressure and it was fine
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)
Tiny
SUNSHINE86
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They are updating their scanner at the shop. They have not seen the truck yet.
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Tuesday, December 15th, 2020 AT 12:21 PM (Merged)

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