Engine sputters under acceleration?

Tiny
HOLMESFAM
  • MEMBER
  • 2003 FORD CROWN VICTORIA
  • V8
  • 2WD
  • AUTOMATIC
  • 93,000 MILES
Vehicle occasionally sputters under hard acceleration
Tuesday, October 14th, 2008 AT 4:16 AM

35 Replies

Tiny
RICK 08
  • MEMBER
  • 54 POSTS
May have a bad plug wire, consider scanning codes This problem will not always turn on check light. a code reader should tell you which cyl is failing if this is the case. Some plug wire sets are costly (as much as a cheep scanner) so the scan might help save you dollars.. These guides will help us fix it.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

and

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down these guides and report back.
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Monday, October 27th, 2008 AT 2:58 PM
Tiny
JACOBFEGLEY
  • MEMBER
  • 8 POSTS
  • 1998 FORD CROWN VICTORIA
I have a 98 ford crown victoria p71 police interceptor that has tranmission shudder. How can I fix it?

Also the car at idle will get a sound like something is slapping in the front of the engine it comes and go's its not always there it shows up more in warmer weather and dosent affect performance and dosent do it when rpm's raised what could it be it has 171,000 miles on it
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Well the shudder could be clutches or torque converter. Nedd more info, How fast are you going before you get it, The slapping? Check the serp belt or anything flapping around under the car. See if the shroud is loose.
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
JACOBFEGLEY
  • MEMBER
  • 8 POSTS
The shudder comes about 25mph and higher and if ya cruze but if ya keep ur foot in it theres no shudder. And the slapping is only at idle and its coming from the engine
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
KEVINLOKEN
  • MEMBER
  • 74 POSTS
  • 1996 FORD CROWN VICTORIA
  • V8
  • 2WD
  • AUTOMATIC
  • 238,000 MILES
Hey there im looking at buying a 1996 ford crown vic and all I was told so far is that it sputters on heavy acceleration and the engine check light is on any idea what this could be thanks
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
DAVE H
  • MECHANIC
  • 13,383 POSTS
Could be numerous reasons for the splutter? MAF sensor. Bad fuel. Clogged injector. Bad pump. Etc etc. Better off having them take the vehicle to a good autoparts store (autozone etc.) And have them read the codes. Most do this free. Repost with the codes for a better diagnosis
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CHUCKYB10
  • MEMBER
  • 17 POSTS
  • 1988 FORD CROWN VICTORIA
  • 5.0L
  • V8
  • RWD
  • AUTOMATIC
  • 66,500 MILES
When driving, it kind of sputters like its not getting fuel, I can drive it like this but it jerks back and forth.
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
That isn't much to go on. You didn't even say which fuel system you have. Some cars still had a carburetor, and some had multi-point fuel injection. About the only thing you can do for this symptom, if you have fuel injection, is to check the fresh air tube between the mass air flow sensor and throttle body for cracks or leaks. If any air sneaks in that doesn't go through the mass air flow sensor, the Engine Computer won't command enough fuel to go with it. That will cause a hesitation or stumble on acceleration.
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CHUCKYB10
  • MEMBER
  • 17 POSTS
Yeah my fault in new to this, 5.0 efi, 302, and it jerks back n forth, usually after about 50 mph, now its acting like this, no matter the mph, I'm a beginner to working on cars, but I want to know everything. All info is very appreciative, thank you
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CHUCKYB10
  • MEMBER
  • 17 POSTS
What is the throttle body?
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
If you think you'd like to get into working on cars, (you sorry sucker :) ), it will make life easier for both of us if you're ready to invest in a scanner. You can find used ones that will work on your car that are very inexpensive, as in less than 50 bucks. I have a Monitor 4000 that does GM, Ford, and Chrysler up to '95 models. It cost over $600.00 new but it's obsolete now. Today I use Chrysler's DRB3 scanner because with an extra plug-in card it will do emissions-related stuff on any car brand sold in the U.S. After 1995. With that card it also works on older Chrysler products so I never use my older scanners anymore. A lot of independent shops also use the DRB3 or other aftermarket products that do even more, so they are selling off their older equipment. That's why you can find them so cheap on places like eBay.

You don't want just a simple code reader. You don't need those for GMs and Chryslers. With Fords, before around '91 or '92, getting fault codes out is a miserable ordeal. It can be done with a test light or voltmeter with a pointer, but it's easier with a code reader. However, the full scanner lets you view live data too. That means you can see current sensor data and see what outputs the computer is turning on and off. Some of the tests are "bidirectional" meaning not only can you see what the computer is seeing and doing, you can talk back to it and command it to do things like turn on radiator fans or the fuel pump for testing those circuits. One of the problems with the early scanners is they only access Engine Computers. My Monitor came with an extra cartridge to access Chrysler's electronically-controlled transmissions, and now I have a cartridge for anti-lock brakes, but the newer scanners can access all the computers on the cars without switching to different cartridges.

By '92 or '93 Ford had made huge leaps with their self-diagnostics, but things really improved with all the '96 models and brands. With those, there's well over a thousand potential fault codes just for the Engine Computer. In '88 all cars were pretty primitive. There may be only two or three dozen codes and they weren't very descriptive. Often they only told you the circuit that needed diagnosis, but not what the unacceptable condition was. You had to figure that out with voltage readings.

The first thing I would do on your car is start with the basics. New spark plugs and wires, and a distributor cap and rotor. Eliminate the easy and common stuff, then if the problem is still there, we'll have to look into fuel pressure and ignition timing. Ignition timing can be erratic if there's wear in the bushing in the distributor or if the timing chain is stretched.

Also check for vacuum leaks. Don't forget that fresh air tube between the mass air flow sensor and the throttle body. Leaks there are a real common cause of hesitations and stumbles during acceleration, and surging at steady speeds.
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CHUCKYB10
  • MEMBER
  • 17 POSTS
Yes I will check for one of them monitors, and I wish I already knew the basics, to auto care, hey thanks, maybe this info could help with my info to you, sometimes it sounds like almost a back fire, its not the original motor its a motor out of a 96 mustang, and wat causes the motor to not stay on when I start it, I turn it over and it will turn off
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
You mean the starter cranks the engine okay, the engine starts and runs after you release the ignition switch, then it stalls a few seconds later? If that is right, the first thing to look at is if you get the nice "idle flare-up" to 1500 rpm when the engine starts. If you do not, ... In fact, if you have to hold the accelerator pedal down 1/4" to get the engine to start and stay running, that is a problem with the idle air control (IAC) valve. The valve itself doesn't seem to cause a lot of trouble. A better suspect is a loose or corroded terminal in its electrical connector. By the way, the clue is the engine WILL stay running as long as you keep your foot on the gas pedal. If it stalls anyway, that is a fuel supply issue.

The throttle body takes the place of the carburetor used on older cars. It just has the throttle blade and controls only the air flow, not the fuel metering. A throttle position sensor sits on the side of it but it has rather little to do with fuel metering. If you don't know what to look for, you can follow the fresh air tube from the air filter to the throttle body where that tube attaches. You can also look for the throttle cable. It's attached to a quarter-round cable guide that sits on the side of the throttle body.
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CHUCKYB10
  • MEMBER
  • 17 POSTS
Thanks for your info, and that sounds like that's the problem, I do have to hold the pedal down. Crazy, so now that's what is wrong, how can I change the idle air control valve.
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
The IAC valve is held on with two bolts, but it doesn't fail very often. Corroded terminals in the connector are more common. Before you spend money on a new valve, measure the resistance between the two terminals for continuity. You can also use a pair of small jumper wires to apply voltage with a flashlight battery. With the engine running, the 1.5 volts should cause a noticeable speed increase. If it does, the valve is okay. If it doesn't, first remove the valve and check that the passages aren't plugged with carbon.
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Monday, October 19th, 2020 AT 4:51 PM (Merged)
Tiny
CHUCKYB10
  • MEMBER
  • 17 POSTS
The connectors need to be changed if they're corroded. How would I do this myself, and have you heard of the big banana scanner.
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Monday, October 19th, 2020 AT 4:52 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
Easiest is to cut off a clean connector in a salvage yard. You can buy most connectors at auto parts stores too. Splice the wires, then seal the connections with heat-shrink tubing. Never use electrical tape because that will unravel into a gooey mess on a hot day. Most of the time the terminals can be cleaned with contact cleaner and a small wire brush. If you can pull the terminals out, you can often use sandpaper too to shine them up.

I haven't heard of that scanner. Look for one from a company that is still in business so you can get updated cartridges or operating information. The Monitor 4000 was made by OTC which made the Chrysler DRB2 that looked almost the same. Snapon is another popular brand but they are very proud of their products and charge accordingly for them. Genysis is another popular brand that is a lot less expensive than Snapon stuff, but I don't know how far back they go.
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Monday, October 19th, 2020 AT 4:52 PM (Merged)
Tiny
CHUCKYB10
  • MEMBER
  • 17 POSTS
Now it won't even start, maybe its outta gas
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Monday, October 19th, 2020 AT 4:52 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
Check the fuel pressure or see if it runs on starting fluid.
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Monday, October 19th, 2020 AT 4:52 PM (Merged)
Tiny
CHUCKYB10
  • MEMBER
  • 17 POSTS
Ok I will, how do I check the fuel pressure, and where would I spray the starter fluid.
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Monday, October 19th, 2020 AT 4:52 PM (Merged)

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