Just a couple of thoughts. If you have a buddy at a parts store, see if he'll let you try a MAP sensor. IIRC they don't need to be screwed down. All there is is a vacuum line and a pigtail to plug in. It doesn't mark the part. If you deal with a part store frequently, they might let you. Just ask in advance & don't try to try it first and them BS them you didn't.
I've done it, but don't tell anyone.
A while back I read that either GM or Ford (I can't remember who) had a tech bulletin out on vehicles that would idle rough or stall when warm. The fix was to clean the back side of the throttle plates with a carbon cleaner. 3M makes one, part no. 08866, for around $3.50 a can. I'm sure there are others that work as well, thats just the number that I remember. Be careful and DON'T scrape the back side of them. Some plates are coated to keep carbon from sticking and scraping could scratch the coating. Try to get all the carbon off. I don't remember why it effects the idle like that, I only know that they say it did.
Good Luck
Karl

 

Thanks. I'll check it out in the morning. We did get our brain in tonight too and we'll be installing that as well. It came from CardOne. They seem like the only ones that make the things any more.

I have some gun scrubber, which is just contact cleaner that should work.

 

Disconnect the spout connector and drive the truck that way for a while to see if the problem persists. If it does continue to run bad then at least you'll know that is not in the timing part of the ignition or computer. If the problem goes away then something is up with either the ign module or the eec-iv computer.My thinking is that the timing is fluxuating up and down causing the engine speed to go up & down.

Another possibilty is the IAC is causing the idle speed to go up and down, but something is causing the IAC to react this way and for right now I'm not sure what could be causing this? Its almost like the eec-iv computer dosent know what the engine speed is and is trying to adjust the idle speed blindly. If the spout connector doesnt eliminate the problem disconnect the IAC and drive it around like that. This is going to be a slow process of trail and error eliminating sensors and engine contols devices.

The dealer cant afford to spend alot of time on this because time is money.

They pay their mechanics a flat rate per job (they are not paid hourly) and they really cant make money on your truck hunting down a problem like this so they just blow you off.

Its unforunate but thats the system. Its also the reason I left the dealers 11 years ago and went to work on trucks. I got tired of ripping off people for a living.

 

To not make any money they've already made almost a thousand dollars and replaced every sensor under the hood. The only things that they didn't replace were the MAP and EEC. I have a new EEC and they suspect with three sensors being shorted (one had a jumper wire on it) that it caused the EEC to go bad. The IAC is new as well because that was the first thing that I changed in the beginning along with the ignition module. One mechanic disconnected it from the computer portion of the system so it was running as bare bones as possible and that's how they discoverd the timing was way off and that I had a bad EGR valve. They also replaced the IPS and ECT along with another wigit that tells it how fast the engine is turning. They have a fancy name for it, but I think it's just a crankshaft sensor. The computer is all that's left because we've basically gotten a new electronic system under the hood. If the computer doesn't do it and the MAP sensor is good then I'm going to have to start over again, but at least it's drivable now. Before it would die and now it just idles rough. I'll also check the throttle plates as suggested to make sure they're clean and not sticking, but you're on the right track when you mention timing because I talked with one of the mechanics and he wondered if it was trying to adjust itself and that's when he said the computer could be bad having taken a shot of juice when the sensors shorted out. Whoever had the truck before us just ran it with bad sensors and never attempted to fix the problem and I'm wondering if it just compounded over time until the EEC finally just failed.

The thing that amazed me dealing with a dealer was how little so many of their employees know about the cars that they work on. Out of ten or fifteen people you find one person that knows a Ford inside and out, but still considers themselves master mechanics. My father, before he became sick and passed away, knew every car inside and out. You could tell him what it was doing and he'd tell you what was wrong with it in a flash using an ohm meter, vacuum gauge, and test light with a screwdriver, but today it seems if the computer doesn't tell them they don't know. Perhaps there's a need to become more mechanic than computer tech instead of the other way around. I say this, but parts has gotten the same way. Unless you know someone that's done it for a while and knows how to use the actual book they only know what the computer tells them. Where are all of the old masters these days?

 

Thats exactly the reason I own old crap, haha. The only thing I got with a computer on it is a '92 Nissan maxima....BTW, Don't ever buy an Oldsmobile Alero. My GF did, and that thing ain't even got a dipstick for the transmission. You have to check it like a manual box, if you can find the plug. Just my 2 cents, but the reason the auto manufacturers don't build anything worth a damn no more, is because they make more money on parts than they do new car sales. Like the person said before, you can't make no money on something that don't break. I know I'm rambling here, but wish you the best on your problem there.

I live around tulsa. If you need a hand with anything, give me a holler.

 

I appreciate the offer. You're just up the pike a couple of hours from me. I have a 2000 F-150 that's just passed 91,000 without so much as a hiccup and the F-350 just passed 101,000 and should be good for another half a million with the straight six in it. I have to say I believe the straight 6's were the strongest engines that Ford ever produced from their 200, 250, and 300, which is sort of odd because his first one was a failure. He refused to ever build another one and it wasn't until he died that they did and they were more successful than anything on the road except the old Chrysler slant 6.

 

Well $&!*. We installed our new brain and it makes it run better - not as starved for fuel then had our MAP sensor checked and it checked good. It still has it's problem and I'll check the brake booster and after that just live with it. It's not as noticable as it was and you can make it die, but it takes a while to do. I'll try again soon when I have a little more money to spend on it tracking everything down and replacing the one or two items that I haven't already. We talked to the guy at Autozone and he mentioned that a friend of his thought there might be a second fuel filter on it somewhere that could play a role, but wasn't sure. He just finished with a truck that has the same exact symptoms and they weren't able to track down the problem on it either - perhaps just a flaw in the model.

I want to thank everyone for all of the help that you've given us. We learned a lot in here and even though we vow not to surrender until we find the problem have decided to try and make a little money with it before we go any further.