Hey everybody, I picked up an 88' F250 SC LB 4x4 with a 460 and C6. Trucks got 109,000 original miles, rebuilt C6 and what seems to be a pretty solid running engine. I gave it a full tuneup with new plugs, wires, cap, rotor, air filter, fuel filter, and changed the oil. Also replaced the TFI module, set the timing, and checked the adjustment on the TPS which was at .91 volts and was working correctly.

So the problem I'm having is at idle when under load and when I take off from a stop. It idles great in Park or Neutral, but as soon as I put it in gear, the idle goes way down, begins to surge and eventually dies if I let it. Then when I take off from a dead stop, it hesitates then takes off really abruptly. Also seems to have a dead spot at 1/4-1/2 throttle when accelerating, but takes off fine when I punch the throttle.

So what do I need to look at next? I'm guessing the Idle air bypass?? But it seems to work just fine as it has a good high idle when cold and in Park. Or is it possibly the exhaust. The Y-pipe has been kind of hacked up and they brought it into 1 with some bubble gum weld, into a Catco Cat, and some factory looking muffler. The exhaust tubing is really small, looking to be about 2-2.25" tubing. So is the exhaust just to restrictive and creating too much back pressure?? Please help as I'm tired of this thing dying at every stop light! Thanks!

 

Well today someone told me to unhook my negative cable to reset the computer. Put it back on and it ran PERFECT for most of the day. Then it slowly started running worse and worse back to square 1. Now there actually seems to be an even worse flat spot at about 1/4 throttle when taking off from a stop, have to punch the gas to get it moving!

Then my CEL came on for the first time. Got a bunch of codes: 2 for the EGR, 1 for HEGO lean condition, 1 for my neutral safety switch and then 2 three digit codes I can't find the meaning for anywhere on the net: 130 and a 164?? So would a clogged up EGR be causing this? Funny how when I reset the computer it ran good for a while then slowly started having the symptoms reoccur. Oh and it doesn't matter whether it's cold or fully warmed up.

Please can someone help point me in the right direction, I'm sure I can figure it out on my own but some opinions and advise may save me a lot of time and money!

 

Does anyone have any ideas or is it just that nobody cares??

 

Your HEGO code is probably caused by the EGR issue as to much exhaust gas in the intake air stream will sure make you run lean. Also the EGR can differently cause your original issue. So fix the EGR which means changing it ans see what happens.

My books does not show 130 or 164 either.

 

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Well so much for my little problems... Something let loose in my engine, what sounded like an exhaust leak quickly became something much worse. Also developed what sounds like a lower end knock. Not what I expected from an otherwise solid clean truck with 109k on the odometer. Gonna pull the engine sometime next week and tear into it to see what I'm dealing with. Oh and I might as well get rid of that pesky EGR stuff while I'm at it!

 

Not with an EFI you won't or you will have a perpetual CEL.

 

Not with Fordfuelinjection.com's little plug-in.

http://rjminjectiontech.com/images/egr_elim1.jpg