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May 16, 2009 | 06:37 AM

Mustspade

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Help Having Problems

Lets see ill start by saying hello to everyone I am new to this site I have heard great thing about this site so ill give a shot. Ill start by telling you about my baby 1988 ford f150 supercab 5.0L 302. About a month ago while driving it started to stumble on accelration and when stop in traffic,red light, stop sign it some times jumps or sputters. So I got out the haynes manual and start pulling codes and testing sensors.Forgot to mention the motor and tranny was replaced about 50,000 miles ago.I have replaced TPS sensor,IAC value,plugs,wires,rotor,dist cap, fuel filter and the soleinod for the EGR value, I have checked all vacuum hoses and repaired leaks, checked most connection on all sensors good, also changed pvc value and hose. still have the same problem I have reset the computer too. I have brought it to three different mechanics and the say they cant help me . got it running better but not right. I recently pulled the codes again and got code 41 running to lean i dont know if the o2 sensors been replaced but i am about to pull my hair out with this problem please any help would be great thanks

May 16, 2009 | 06:54 AM

Lazy K

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Joined: Jan 2005

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Sounds like you have a weak fuel pump. I would think you should check the fuel pressure.
Hopefully some of the EFI experts will chime in soon.

May 16, 2009 | 08:00 AM

subford

Fleet Owner

Joined: Aug 2005

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From: Easton,Ks

Do you have one or two tanks?
If so does it do it on both tanks?
Can you run off either fuel tank (will it switch to the other tank)?

My guess is bad in-tank fuel pump(s) but the above information could change that.

May 16, 2009 | 09:16 AM

Mustspade

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Hey again

It does have two tanks and both run the same it doesnt matter if i switch the tanks the truck still sputters and jumps. I will look into the fuel pump would it throw a code if it was bad? I did mention i Got the code 41 what does this mean it was when i peform the test koeoR test.

May 16, 2009 | 09:44 AM

subford

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Joined: Aug 2005

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From: Easton,Ks

Quote:

Originally Posted by Mustspade

It does have two tanks and both run the same it doesnt matter if i switch the tanks the truck still sputters and jumps. I will look into the fuel pump would it throw a code if it was bad?

You need to check the fuel pressure with a fuel pressure gauge hooked to the fuel rail with pin #6 of the self-test connector grounded.
You should get around 42 PSI. You may also want to drive it with the gauge someplace that you can see it to make sure the fuel pressure does not go be low about 32 PSI at any time. While driving it should be about 32 PSI while at idle and about 40 psi at WOT.

If the fuel pressure is OK then change out the TFI module on the side of the distributor.

Quote:

Originally Posted by Mustspade

I did mention i Got the code 41 what does this mean it was when i peform the test koeoR test.

Yes you said that above and yes if it came during the EOER self-test it happened when you did the test.

May 17, 2009 | 06:49 AM

Mustspade

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thanks for the reply

i will take that advice and try that if it dont hold pressure does that mean i have a bad fuel pump or does it mean bad FPR? thanks subford for all the help

May 17, 2009 | 07:15 AM

rikard

Posting Guru

Joined: May 2007

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From: North Reading Mass

Usually a FPR will fail because the diaphragm inside will start leaking. You can check this by pulling off the vacuum line and checking for fuel in the line. The FPR regulates fuel pressure according to engine load (vacuum). If you pull off the line while the engine is at idle the pressure will go up.
regards
rikard