Hi all. I have been reading many great posts, but cant find anything that really fits my grievous Beast.

1990 F250 4X4 302 cross throttle body injection, E40D, 200,00 km (160,00 miles), all stock. Used for everyday driving, pulling small horse trailer, or two snowmobiles. Nothing heavy.

Serious stuttering/slamming/missing/skipping whichever word we want, and surging idle, not when dead cold, but after about 5 minutes driving, progressively worse as it gets warm, then "check engine" comes on, BUT it seems to be at a fairly specific RPM range - 1200 to 1800- and clears up quite a bit if I shift down to Drive, or punch the pedal to kick it down. Very bad pulling up a long hill, hammers so hard that it slows to near death, and I have to pull over. However, it is getting much worse quickly.

Has been scanned, replaced O2 sensor, temp sensor, checked EGR, new fuel filter/cap/rotor/coil wire, good wires and plugs. Have run injector cleaner/fuel drier through both tanks.

Where do I look next? TPS? Injectors? Fuel pumps? Distributor? If it were my old carbed truck, I would rebuild the carb, cause it would likely be accelerator pump etc. Oh, and the tranny is tired and crappy, could something be with that? MPG is really bad, about 8 without a load, 6 with a load....

I am an ex-parts/service person, and can no longer do major repairs myself, and have to rely on shops. So, any thoughts? Thanks.

 

Every EFI Ford truck produced was multi-port fuel injection. I have no idea what system you're describing, but if it's an accurate description it's not stock at all.

You kind of gloss over the codes. If the CEL is lit, the computer is trying to tell you what's wrong.

What codes are present now? You can pull them with a paperclip. Check out http://broncodata.com/tech/codes.htm

 

You may check your fuel pressure regulator for vacuum, also check for fuel in the vacuum line. Check your pressures with a fuel pressure gauge, make sure you got the right pressures. This sounds similar to recent post, here:

https://www.ford-trucks.com/forums/7...e-41-help.html

IF that all tests good:

I would also look specifically at the Air Solenoid and the TPS. Since it clears out at full throttle, I would think the TPS is at least sending a signal, as full throttle kicks it to a "default". I guess in short, I would suspect the IAC first, if it's not fuel pressure....

 

Hi Andy, thanks for you reply, I will have to admit publicly that I have been a Chevy Gal for 30 years, and this is my first foray into the world of Ford, forgive me a bit, eh? Also, I am a PWD and cant do my own diagnostics, my serviceman didnt tell me the codes.

And, BChance, thank you!!! I called in to get my truck in to the shop and check out your suggestion. Gives me a direction.....

Thanks
C

 

Hope it works out for you, let us know.. at the very least, if you can get the codes and post them, that is a HUGE help!

 

Sorry, didn't mean to come down hard on you.

You *can* do your own diagnostics. All you need is a short piece of stiff wire (paperclip works great) a pen and a piece of paper.

 

just a thought you should have the mlps changed or as autozone called it the neutral safety it evects shift points and how it shifts its a 37 dollar part and it stoped mine from missing shifts