looking at the 95 vacuum diagrams on there, the 95 is totally different. it seems there is only the one valve on the canister. but being that it still must function the same as its doing the same job, i would try to plug the vacuum line going to it, on the side going toward the engine. see if the engine runs better.

as far as the the ect and iat, its free to check but i think you are on the wrong track. i have had many gm'* and dont feel like i have gotten my money unless its got 2-300k before i get rid of them and i have never replaced a temp sensor

thanks, jwfirebird. I will try plugging that line. Also gonna go ahead and retest the IAT now that I have the right values to check against. It is running quite well now, just have the CEL. I am just dreading that it is the O2, or worse nightmare of all, EGR. Not a clean or easy way to deal with the EGR. You guys had those go out? Any tips? Any part more likely to light up the CEL than others on these? Oh; I guess I should unplug the IAC then start the engine, put it in drive and see if the RPMs drop? And if so, IAC is probably working?

Mealness

egr- the valves themselves can be cleaned and lubed some times but the 3800'* have that flexible metal tube that likes to crack

if it starts and runs, the iac is fine, not something you want to mess with unless you have to.

i think i would try to find someone with a 1.5 scanner if its running fine, shots in the dark at this point, maybe a small shop that wont charge an arm and a leg to scan it

jwfirebird - you're right, and I talked to my buddy the smog guru and will take the car in tomorrow. Sounds like no big deal for him to scan it.

I wanted to take care of everything I could first and not waste his time so tried a few last things. I went back to easyautodiagnostics.com and took another look at the EGR stuff. I went ahead and pulled the valve from the engine and checked the variable voltage numbers from the valve to the PCM when the pintle is manually raised, and confirmed that it is working properly. I also tried to fire up the engine with the valve off, couldn't, and saw that it kicked back through the open holes somethin' fierce, all good. I recently did the same functional test on a 4.6 Ford and it didn't even stumble much, indicating blockage of the EGR passages. So the EGR system is in good shape.

I plugged off that EVAP line, cleared the computer, and fired up the engine and confirmed that the CEL still lights up. I also double-checked some resistance readings at the IAT, ECT, and IAC, and decided that there is nothing conclusive there at all to suggest any faults. So it'* off to my buddy. Oh, figured out why the serpentine belt is riding on the outside of the water pump and tentioner pullies; somebody put a nut behind the alternator mounting, apparently to space it out a bit. WHEN the car passes smog tomorrow, that will leave me free to hit the yards where I know there are several '95s, and I will get all that annoying stuff handled. Will advise progress tomorrow,

MealHopeful

it isnt a big deal, the only people who will tell you it is are trying to charge a ridiculous "diagnostic" fee. i heard from 50-100 bucks to plug in a scanner and look at the screen

Code(*) won't scan; PCM won't talk to the scanner. Guru is aware of the OBD 1.5 thing, been doing this since well before '95, doesn't have an answer at this point. Had me test continuity from serial data points on the PCM to the data link interface (circuit 800) because he thought there was an open there, but no dice. Hey, can a disconnected rear knock sensor cause a CEL? If I can get the light out, it won't matter if he can scan it or not,

MealNotToday

Yes, a rear knock can cause it.

wow...I'll feel stupid and happy at the same time if that turns it off...

Meal-Ricer-Type-R (whatever that is)

Why, was it disconnected?

Just a quick clue, if you disconnect the battery to clear the codes, reconnect, and start it up, if the CEL immediately comes back on, something is disconnected. Otherwise, it may take awhile for the PCM to detect an actual issue.

Yes, I'm pretty sure the wire to the rear is hanging down, disconnected. The front was too, and needed a new connector spliced on, so I did that. I would say it takes about 8-10 seconds for the CEL to come on after clearing. --

RiceMeal