Yea, maybe 6000 is a little much. I had to do the test three times the first time I tried to pull codes on my '92 because I wasn't doing the WOT test right. I ended up just jamming the throttle and letting it redline. It worked then.

Looks like you quoted my post before I edited in the link for the EGR position sensor. Look here:
Ford Fuel Injection » EGR Valve Position sensor (EVP)

 

Man, I don't think my tired engine would go to 6000 RPM. Maybe for a split second, haha. Very helpful link on the EGR sensor, thank you Anafiel. I will ohm it out while moving the diaphragm to a few different positions. And I'll back probe the wires and check for proper respective V while running the engine.

It ain't the brake booster. It's fairly new and works great... now, haha.

If the EGR sensor is bad, which so far it seems it is, it wouldn't make the ECM lower RPM to a lopey idle, would it? Even if it was getting falser EGR position readings...

I bet it needs the EGR sensor and an IAC.

 

My TPS was only off by a tenth of a volt but it was enough to make the ecu flutter the evp and keep the egr barely open at idle. Do you get a clicking from the relay bank like in my video?

 

Make sure you have no other vacume leaks , and have you cleaned the Throttle body around the throttle plates? before 1992 they were not sludge tolerant and needed to be cleaned from time to time, when I worked at the dealership I always cleaned T/B sametime as IAC and then perform idle relearn ---So when done cleaning remove ground cable from battery for 5 min( clears learned memory). then put back on/ start truck, let it idle in park 2min/ then in drive 2min this will let it relearn Idle. see if this helps it has worked for me many many times-- But make sure no vacume leaks--

 

Also when you do a running test just --SNAP throttle all the way to Floor --The Computer just wants to see Wide Open Throttle Voltage for an moment, and those egr sensors were always a problem, but as long as the EGR valve is not leaking (not off of seat) it will not cause an idle concern

 

I'll try it that way next time I pull codes.

Maybe I did it right the last time because I was pissed because my code reader kept telling me I was an idiot!!

 

Cleaning the TB and IAC were the first things I did when I got the truck 4 yrs ago to get rid of a stalling issue. I recleaned the IAC the other day. I can't imagine the TB getting gunked up again since I run it fairly hard fairly often. But, I'll look at it.

I just briefly snapped the throttle the WOT stop with my hand under the hood. Maybe my TPS is out of adjustment enough that it never gets close enough to 100%, hence the code 77 and other probs.. I'll have to do some V checks on it.

Man, I'm pretty sure there ain't more vac leaks. I'll check again, tho. There are plenty of vac lines.

 

A bad IAC is one of the most common problems with ford fuel injected controls. Once you start messing with it, patience is recommended.

It may take a couple of attempts to get it right. Disconnect the negative battery lead for 15 minutes. Turn the key to on but do not start it and set your TPS to .90 volts. Start your engine without your IAC hooked up. You will probably have to blip the throttle manually to keep it running. Then set the hard idle to 650-700 rpms. Then hook up the IAC and it should run at a correct idle.

That sounds easy doesn't it. It's a pain in the bass. If it doesn't idle with the IAC hooked up it might be bad.

Patients, driving the vehicle between settings and repeating the steps will get your desired results.

The TPS should ideally be set as close to .99volts, with the engine running, as possible for performance or above .90 for consistency.

 

Thanks for all the help everyone! I got rid of all the codes except for the 44 AIR injection code, but I ain't worried about that, I removed the smog pump years ago.

I back probed the TPS and found only ~300 mV at idle. I raised the stop screw for about ~950 mV throttle closed. The TPS had a smooth range V signal but was grossly off.

For the code 31 PFE/EVP below .24V, I discovered that sure enough, with the EGR fully closed at idle, it only showed something like .05V. The EGR is about a yr old. I replaced it back then b/c it would not hold vac, the diaphragm was leaking. Well, evidently this new one, for whatever reason, even when fully closed does not move the pintle up enough for a ~.24V signal. So, I taped a piece of cardboard and put it in there to raise the pintle up for ~.24V. It worked!

The codes 18 and 25 went away once I made these fixes. I don't know why, but I ain't complaining.

Now, it runs well, a little better maybe. If I start it cold, the fast idle works great, but if I start it warm, there's a good chance it will start and stall immediately, or at least drop way down in RPM after starting for a moment. And it still will intermittently idle with a lope at 450 RPM in gear. I think it is the IAC being weak, but not bad enough to throw a code.

 

Disconnect your battery for ~10 minutes, reconnect it and start it up, let it re-learn the idle adjustments.

 

I was thinking that would be a good idea. Thanks dude, I'll do that. It was acting like this before the adjustments, but it's definitely worth a try.

 

Mine still stalls occasionaly when it idles down from fast idle, I believe it has to do with the AIR and the ecm looking for extra o2 that is not there in regards to the mixture. The passages in my heads are clogged and I'm too lazy to clean them out with a speedo cable. It runs fine after the first stall. The rest of my system is operational. Sometimes it wont stall but idles down low and comes back up. I'm fine with it.

 

i have same thing happening with my truck what did you do to fix it please help not to good on computer if you could call me @619 313 7564 that would be a big help need help it is my work truck thank you

 

subbing for later