I bought a well cared for , original owner 99 expy eb for my wife last fall and it is teaching me new curse words with the issues I've been trying to deal with. When we bought it there was a very slight torque converter shudder that was cured by flushing tranny completely and replacing the fluid, filter, and friction modifier additive.
It then ran great for a few months until it started running rough and eventually the CEL came on and showed codes for 3 of the COP's , I can't remember which ones right now, so I replaced all 8 as well as the plugs. The vehicle would die when put in gear so we had it towed back home for me to do the work and after replacing everything it still runs rough and will die when put in gear. I also replaced a few vac fitting and the pcv hose including the fitting at the intake in the rear and the IAC while I had the throttle body off to clean it and to access the pcv fitting easier.
After all of this it still runs very bad missing and all of the injectors check out fine with a noid light and checked with an LED tester, also checked cop connectors with the LED tester and they checked ok, I don't have a cel and no codes right now but the IM monitiors aren't all ready and I can't drive it to finish the OBD2 drive cycle. Any suggestions ?

 

Did you check line fuel pressure? Has the fuel filter been replaced?
I would still guess vacuum leak, not sure if you did, but replaced that pcv elbow over the passenger valve cover area anyways.

 

Have you cleaned or replaced the MAF sensor? That's the one inside the engine air intake duct.
RockAuto Parts Catalog

 

Oh yeah, I forgot to mention that the fuel pump and filter had been replaced a few months before I bought it and the work was done at the Ford dealership. I did check the fuel pressure anyway though and it checked out fine. The pcv elbow has been replaced and a couple other vac fittings that looked suspect but it still runs very badly.
It almost acts like it is in limp mode but there is no light or code and since it dies when put in gear I can't complete a drive cycle. I'm starting to wonder if the ecm is jacked up.

 

I did clean the MAF sensor and it made no difference. I also replaced the replacement coil packs by swapping out two others that I bought just in case I got a faulty one. I went through every one and no difference so that rules out a faulty new cop.

 

You have not said if the truck has run properly after your tune up .
Could you have possibly have gotten the wrong plug connector on the wrong coil packs ( I am not positive they will even reach another coil but is is worth a shot )

 

You have not said if the truck has run properly after your tune up .
Could you have possibly have gotten the wrong plug connector on the wrong coil packs ( I am not positive they will even reach another coil but is worth a shot )

 

I marked all connectors with rubberbands, 1 for front cyl, 2 for 2nd etc., so I know that they are all connected to the proper cop It hasn't run right since I installed the cop,s and plugs etc. and that was done because of the original problem that showed a code for 3 of the cop's and I decided to just replace all cop's and the plugs. I also forgot to mention that I did use motorcraft plugs when I changed them.

 

I also need to add that I checked voltage of the battery and the connections and everything checked out fine there. If I bought a used computer would that help my situation ? I don't think it will show a code with the current ecm because it won't run long enough to complete a drive cycle.

 

Have you tried reading the codes? I had an intermittent miss on my '99 Expedition, but it would never throw a code. I kept checking with Torque Pro using my smartphone, bu no codes nor a CEL. I finally downloaded Forscan (it's free) and used it to read codes. It showed a pending misfire on COP#4 plus some other codes I was unaware of. I replaced COP#4 and problem solved.

I would download Forscan and try read the codes. You might have one pending but since you can't complete a drive cycle it will not throw the code and light the CEL.

 

I have a Innova 31603 and it checks for pending codes and it's coming up with nothing. This thing is driving me nuts trying to figure it out but I'm not giving up.

 

A little update on this problem. I put it on the back burner for a little while and finally had it towed to a reputable local shop and found out that the torque converter is bad so I'm looking at trans rebuild or replacement. Since money is tight I'm going to do a little research and try to rebuild the tranny myself. This could be interesting.

 

Why would you do a rebuild or replace the tranny if it's just the TC that's bad? Just replace the TC, the fluid, and the filter.

 

well, they told me that the clutches were bad too and if I'm gonna drop the tranny then I'll just do the rebuild and be done with it. The shop is owned by a buddy of mine that I've known for over 20 years and he recommended the rebuild or replacement and even found a few used tranny's in case I wanted to buy one and out it in on my own. i just don't want to take the chance with a used unit and possibly have more problems soon.