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Engine hesitates and sluggish acceleration

Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
That's what we do!
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Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
THOMPSOND134
  • MEMBER
  • 2 POSTS
  • 1997 FORD F-150
  • 4.2L
  • V6
  • 4WD
  • MANUAL
  • 189,000 MILES
Truck has no power. When taking off. The more gas its given the weaker it gets till it reach high 2000. No Smell of raw gas no hiss from under hood took off cats no glog Good tune up. No smoke from exhaust. And always back fires from exhaust. When shifting gears till 4 and 5th gears are reached. Takes about 100 ft to get to 30to40mph.
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Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Have you check the mass air flow sensor? If not get some mass air flow cleaner first and try cleaning it, if that don't work then unplug it and see if it runs any better. With it unplugged it won't have a great throttle response. Let me know what you find and we will go from there. Please go over these guides to help find the issue.

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

and

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

Please run down these guides and report back.
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Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
THOMPSOND134
  • MEMBER
  • 2 POSTS
I have cleaned, in the beginning of all this never unplugged. Not sure how much worse the throttle response can be. But thank you very much. I do appreciate you working with me.
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Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Let me know how it does when you unplug the mass air flow ok.
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Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
CLYDE RAINES
  • MEMBER
  • 1 POST
  • 1996 FORD F-150
  • 6 CYL
  • 2WD
  • MANUAL
  • 223,567 MILES
It has rough idle motor shakes really bad and it won't go over 15 miles an hour. Can't get out of there gear. I have replaced the MAP sensor the idle air control valve, plugs wires, injectors and cut out catalytic converters. Still does same thing. Please help
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Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Let's start with checking for codes. Then we need to check for a vacuum leak as the intake manifolds have been known to leak on these engines.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, you said you replaced the MAP sensor but did you do anything with the MAF sensor?
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Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
WALTER WOOD
  • MEMBER
  • 24 POSTS
  • 1995 FORD F-150
  • 5.0L
  • V8
  • 4WD
  • AUTOMATIC
  • 297,000 MILES
Truck runs awesome when it is first started up, drives beautifully but the check engine light will come on for a second then go off and I lose all power. It lowers the idle to 500, chugs and if I try to give it gas it just pops through the intake system. It has a fresh tune up, new fuel pump and filter, and a new vacuum canister purge solenoid. Nothing seems to fix it. I cannot get it to duplicate the problem in the driveway at idle it would rather strand me and have to be towed home.
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Tuesday, June 29th, 2021 AT 9:07 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

Do you have the code? I need the code to help with the area of failure. Please go over these guides to help find the issue.

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

and

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

and

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

Please run down these guides and report back.

Roy
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Tuesday, June 29th, 2021 AT 9:07 AM (Merged)
Tiny
WALTER WOOD
  • MEMBER
  • 24 POSTS
I have the reader for KOEO it is 565 Continuous code is 512 and KOER the codes are 538. 536. 632. The engine light is very intermittent, I just had it idling for an hour, power braked it to simulate being under power and nothing, stayed running great.
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Tuesday, June 29th, 2021 AT 9:07 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
512 is the key. The KAM or keep alive memory looks like the issue. The ECM is bad.

NOTE
KOEO refers to Key On Engine Off (KOEO)
KOER refers to Key On Engine Running (KOER)
DTC refers to Diagnostic Trouble Code (DTC)
DTCs should be diagnosed in the order they are received.

DTC 511
Powertrain control module Read Only Memory test failure, KOEO self-test.

KOEO Hard Code - Replace Powertrain Control Module.

KOER Hard Code - Replace Powertrain Control Module.

KOEO Memory Code - Replace Powertrain Control Module.

DTC 512
Powertrain control module Keep Alive Memory test failure.

KOEO Memory Code. Go to QB1

DTC 513
Powertrain control module internal voltage failure, KOEO self-test.

KOEO Hard Code. QD1
See: Computers and Control Systems > Pinpoint Tests > QD1 - Diagnostic Trouble Code 513

KOER Hard Code. QD1
See: Computers and Control Systems > Pinpoint Tests > QD1 - Diagnostic Trouble Code 513

KOEO Memory Code. QD1
See: Computers and Control Systems > Pinpoint Tests > QD1 - Diagnostic Trouble Code 513

DTC 519
Power Steering Pressure switch circuit open during KOEO self-test.

KOEO Hard Code. Go to FF1

DTC 521
Power Steering Pressure switch circuit did not change states during KOER self-test.

KOER Hard Code. Go to FF5
See: Computers and Control Systems > Pinpoint Tests > FF5 - Verify Operator Interaction DTC 521

DTC 522
Vehicle not in "PARK" or "NEUTRAL" during KOEO or Park/Neutral switch circuit open.

KOEO Hard Code. Go to TD1
See: Computers and Control Systems > Pinpoint Tests > TD - Transmission Range Sensor

DTC 525
Indicates vehicle in gear or A/C "ON" during self-test.

KOEO Hard Code. Go to TA1
See: Computers and Control Systems > Pinpoint Tests > TA1 - System Identification

KOEO Memory Code. Go to TA1
See: Computers and Control Systems > Pinpoint Tests > TA1 - System Identification

DTC 527
Park/Neutral Position switch circuit open or A/C on KOEO self-test.

KOEO Hard Code. Go to TA1
See: Computers and Control Systems > Pinpoint Tests > TA1 - System Identification

DTC 528
Clutch Pedal Position switch circuit failure.

KOEO Memory Code. Go to TA1
See: Computers and Control Systems > Pinpoint Tests > TA1 - System Identification

DTC 536
Brake On/Off circuit failure or not actuated during KOER self-test.

KOER Hard Code. Go to FD1
See: Computers and Control Systems > Pinpoint Tests > FD1 - Verify Brake Was Pressed

KOEO Memory Code. Go to FD90
See: Computers and Control Systems > Pinpoint Tests > FD90 - Check For Proper Stoplamp Switch Installation

DTC 538
- Insufficient RPM change during KOER dynamic response test.
- Invalid cylinder balance test due to throttle movement during test.
- Invalid cylinder balance test due to cylinder identification circuit failure.

DTC 632
Transmission Control Switch circuit did not change states during KOER self-test.

KOER Hard Code. Go to TB2
See: Computers and Control Systems > Pinpoint Tests > TB2 - Diagnostic Trouble Codes 65, 632 and 653

DTC 565
Canister Purge circuit failure during KOEO self-test.

KOEO Hard Code. Go to KD6
See: Computers and Control Systems > Pinpoint Tests > KD6 - Check VPWR to CANP
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Tuesday, June 29th, 2021 AT 9:07 AM (Merged)
Tiny
WALTER WOOD
  • MEMBER
  • 24 POSTS
I was afraid of that. Now this one accesses from under the hood? Drivers side?
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Tuesday, June 29th, 2021 AT 9:07 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Yes it is. It is under hood, drivers side.

Roy
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Tuesday, June 29th, 2021 AT 9:08 AM (Merged)
Tiny
WALTER WOOD
  • MEMBER
  • 24 POSTS
All other codes are gone. I went ahead and ordered a new mass air sensor and installed it worked great! Thank you.
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Tuesday, June 29th, 2021 AT 9:08 AM (Merged)
Tiny
TONYD2355
  • MEMBER
  • 4 POSTS
  • 1995 FORD F-150
  • 5.0L
  • V8
  • 2WD
  • AUTOMATIC
  • 54,000 MILES
Will be driving along fine for about 20 miles, then the engine loses power like it is going to shut off. Pushing gas pedal to floor and it sputters. Some times it backfires. Engine light pops on then I switch to the reserve tank and the engine light goes off and the truck running and drives smooth. For some reason this only happens while using the main tank. Does this truck have a fuel pump driver module? If so could that be the problem?
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Tuesday, June 29th, 2021 AT 9:08 AM (Merged)
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
There is no driver module on this truck. It sounds like the pump in the main tank has gone bad. When replacing the pump, inspect the tank for rust. The last one of these trucks that I worked on ate my lunch because I did not check for rust and I had to eventually remove the tank and send it to a local radiator shop so they could acid-dip it.
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Tuesday, June 29th, 2021 AT 9:08 AM (Merged)
Tiny
TONYD2355
  • MEMBER
  • 4 POSTS
Thank you!
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Tuesday, June 29th, 2021 AT 9:08 AM (Merged)
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
No problem!
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Tuesday, June 29th, 2021 AT 9:08 AM (Merged)
Tiny
MARSHA MORRIS STURGILL
  • MEMBER
  • 2 POSTS
  • 1995 FORD F-150
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 95,000 MILES
The truck starts fine. After driving anywhere from a quarter to a half-mile the truck slows down as if I took my foot off the gas pedal. I have to floor the gas pedal and let up, then it roars back to life, only to do it again over and over. Three different mechanics have tried everything they can think of that could go wrong under the hood. No one has checked anything pertaining to the gas tanks. It doesn't matter which tank, the problem persists. The truck doesn't have a computer to plug into to run diagnostics. Any help sure would be appreciated. Marsha
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Tuesday, June 29th, 2021 AT 9:08 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

My first suspect is fuel pressure or even a faulty catalytic converter. I have seen converter insides come loose and rattle around causing a blockage of exhaust from the engine. Do you notice any rattling?

Do me a favor. Although this doesn't have an OBD2 design for a scan tool, you can still retrieve diagnostic trouble codes. Here is a link that explains how to do it without using a scanner:

https://www.2carpros.com/articles/ford-lincoln-mercury-obd1-1995-and-earlier-diagnostic-trouble-code-definition-and-retrieval

Try that and let me know if anything is found. If not is, then I feel we should check fuel pressure.

Let me know.

Joe
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Tuesday, June 29th, 2021 AT 9:08 AM (Merged)

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