I've been having a problem with my 88 F-150 4x4. It starts up great and after about a half minute or so starts to idle rough. I've checked and changed a few things in the last few months. Air cleaner, O2 sensor, new plugs, wires, injector cleaner. Any way I took it to a local mechanic(certified) and he checked it out and could only find one thing that may be the problem. He found a service bulletin that said the EEC unit on my truck should be replaced. The old one would affect the idle after 25 seconds. We decided to check into that and Ford says they have discontinued the replacement EEC.
Does anyone out there know where I could get one? I was also considering a Superchip, would that override the stock computer and take care of the problem?
Any help would be appreciated.
Please email me at ronmalt@cot.net

Thanks, Ron

 

When you first start your truck when its cold it will high idle for about 30 sec to a minute. It is supposed to do that. Have you cleaned the throttle body and butterfly valve?

 

Yes it does idle down to the normal idle speed. The longer it sits at idle the rougher it gets. It also idles rough after driving at slow speeds <30mph for awhile. I just talked to the mechanic and he has had no luck with any eec-iv unit he's checking out a few other things now but doesn't want to run up a big labor bill for nothing. He's run cleaner thru the injectors and checked the butterfly valve etc. Now were hoping it's something other than the eec-iv unit if we can't get one.

Any help from anyone would certainly be appreciated.

Thanks, Ron

 

Ron,

I have the identical problem with my 93 F150, 4.9L (150,000 miles) and have not found the problem.

So far I have replaced the idle air bypass valve, cleaned the throttle body, checked the TSP and oxygen sensor, bypased the EGR, replaced plugs, wires, distributor cap and rotor, used a couple of cans of fuel injector cleaner, checked for vacuum leaks.

Have you been able to fix your idle problem?

 

Pastmaster,

I bypassed the EGR because I read if the EGR fails it could cause a rough idle by returning exhaust to the intake manifold during idle instead of only at higher speeds.

I read an article of how to do it. What I did was to loosen the EGR enough to slip a copper plate about 1/16 inch thick and large enough to block the opening from the EGR to the intake manifold and retightened the EGR. Be CAREFUL to tighten the EGR evenly and not too tight or it may crack. I then plugged the vacuum line going to the EGR.
The article I read said some people notice a little more power since exhaust gases are not being mixed with air in the manifold.

I used copper to block the opening because it seemed to seal nicely. I got the copper from a copper plumbing fitting. I just cut it opened and flatened it with a hammer. I worked great!

The article showed removing the entire EGR and making a cap to cover the opening in the manifold. My way seems to work and only takes a few minutes once you get a piece of metal to slide between the manifold and the EGR

Good luck!

 

Jim: Just out of curiousity, how do you bypass the egr? I know that it is the (exhaust gas regulator) but does it help the engine if you bypass it? I would be interested in doing that on my 93, also we don't have sniffer tests here...Thanks in advance for the info!

 

Ron:

I was wondering what motor is in the truck?
the 4.9 or 302. And have you checked the junk yard for a EEC-4? I have the 4.9 and it also gets the shakes after its started. Ive been told its just the nature of the beast.


Thanks Mike

 

Mike, I've got the 5.8L in mine. One tech said the same thing you said. They just don't idle all that smoothly anyway. I got mine back last night and the tech said he wasnt satisfied, did'nt charge an arm and a leg but still had to pay for his time. Anyway the few things he did that I didn't do, run injector cleaner thru it, changed the timing a little seemed to help some. I brought if home and let it idle for about a 1/2 hour and it ran fine. I shut if off for about an hour drove about 15 miles and right back to the rough idle although it doesn't stall out like it was doing. He said he noticed that it was and intermitent problem. Guess he was right. I think I located a source for the EEC-IV module. I can't decide if I should buy one or not. If they'll let me return it if it doesn't do the job I might give it a try. How about catalytic convertors, can they cause the problem? Any help would be welcomed.

Ron G.

 

armsrus1,

Has your 4.9 always idled roughly? I have a 4.9 and it used to idle so smoothly it was hard to tell it was running.

The last few months it has started to idle roughly and I haven't found the problem. Though I've tried a lot things.

Jim