7.3 surging ?

[smokin joe]

I have a 1997 powerstroke and at times it surges. It desnt run smooth and when you press the foot feed down it doesnt gradually accelerate. When you press the foot feed down it takes off right away. When I am going down the road it either runs fast or not at all. It almost acts like it is a gas 8 cylinder that has a spark plug that is fowling out. I replaced the fuel filter & air filter. I have been reading other posts and was wondering if it could be the cam sensor? If not.....anyone have any suggestions????

 

[JOAT]

First off, Welcome!!!

Don't know the history of your truck, but I'll make some suggestions.

The issues you have are not 100% specific to any one problem, but there are things you can try to narrow it down.

First, if you have a chip installed, remove it temporarily to eliminate it as a contributing factor.

Check your oil level, and consider changing the oil if it hasn't been done recently, as oil breakdown can result in foaming.

Next, pull the fuel filter and check the FPR screen. It's in an opening in the upper drivers side part of the filter housing. Make sure it is clean, or air will build up in the bowl and get to the injectors. Also fuel starvation due to a failing fuel pump can cause int loss of power

Make sure the tin nut on the back of the IPR is not loose.

Is the tendency to take off right away intermittant? Could be a problem with the throttle position sensor.

Pull the oil fill cap and sniff inside. If it smells like burnt electrical, could be the under valve cover wiring is frying.

Does it have a 10k mod? On the front top of the drivers head is a sensor with three wires (ICP). Check it for a resistor or diode jumpered between the wires (10k mod). If it has it remove for now. It increases power but can cause a touchy throttle.

Let is know what you find,
Don

 

[95_stroker]

Could be a problem with the throttle position sensor.

Without knowing all the specifics about this truck, my gut wants to agree with the TPS diagnosis.

 

[JOAT]

Without knowing all the specifics about this truck, my gut wants to agree with the TPS diagnosis.

This is one of those "if I could only test drive it" kinds of problems

 

[smokin joe]

Thanks for the reply. WOW, you guys know your stuff ! If I can figure all this out I will try it and let you know. I dont know where a chip would be if one was installed though. Thanks for all your help. First time diesel owner......

 

[JOAT]

snip... I dont know where a chip would be if one was installed though...

Where the emergency brake is, remove the plastic trim. Back in behind there hard to see is the PCM. If there is a chip it will be plugged into the end towards the back of the truck. They are kind of notorious for working loose and causing intermittant issues. Hopefully it is that simple.

 

[95_stroker]

Joe,

How long have you owned the vehicle? Can you give us some history on the vehicle? How many miles, performance mods etc etc? Did the problem come on recently? Did the problem come on after some recent routine maintenance?

If you go to your userCP and fill out a signature line with specific info about your truck it may help us help you faster.

 

[smokin joe]

I just changed the oil 3 weeks ago and I couldnt find any chip so I thought I would check the FPR screen. When I did it was BLACK and VERY plugged. I replaced it and so far (knock on wood) it has been running great. Thanks for all your help guys ! Your better than the local Ford Dealer. )

 

[JOAT]

Cool. Thats something you need to check every time you change the fuel filter. Very common problem.

By "changed", do you mean the filter? The FPR screen is in the 1/4" hole in the side of the housing, and usually just gets cleaned.

 

[smokin joe]

I actually dropped the FPR screen and couldnt find it. It is lost forever in the engine. I had to buy a kit that cost $80......Holy cow, just for a screen and some o-rings. I shoulda made the screen out of a faucet screen. What a rip. Do you know where to get JUST THE SCREEN????