okay, i'm in the automotive tech program at school... unfortunately, we're on auto brakes and suspension and steering... so i haven't made it to the engine diagnostics yet lol... at any rate, i have full access to the shop and all of their tools plus my own.

my 96 trans am started having problems in the rain after i put a K&N FIPK on my car. it would start lagging really bad... at idle at lights, the RPM's would drop and it would try to die. under moderate acceleration, it would cut out and have a hard time accelerating at times, then it would break loose and accelerate normal. i took the FIPK off, and put the factory air intake back on. afterwards, it seemed as if the problem had cleared up, the car ran fine in the rain even. then, it rained like 4 days straight... the car did fine for the first few days, then it started acting up again. after the rain cleared and it dried up, i figured it would go back to normal like it always did... but the car kept doing the same things, except worse and it wouldn't ever stop completely. then my SES light would start blinking when it was doing it. so naturally, i put it on the diagnostic at school... it brought back 10 codes. 4 were o2 codes that were from the removal of my rear o2's when we installed my headers... 2 rich codes, 1 lean (i haven't got my o2 sims in yet)... then one was the EGR which we also took out... the last 2 were the ones that should've been the problem... one was the MAF sensor and one said it detected an engine misfire...

so i replaced my MAF sensor today, and the car is STILL doing the same thing and the light is STILL blinking. i don't have access to the shop right now or again until monday, so i can't further diagnose the problem. i put it on a hand-held scanner at crappy autozone... and it STILL pulled the MAF code which makes no sense since i JUST put the new MAF on today. i have tried to figure out what the problem is, but to no avail... the car isn't misfiring, there are no backfires that would indicate burnt wires or shot plugs... and i'm not sure what else would trigger the engine misfire code, and i have no clue why it would still set off an MAF code.

can anybody help me out here? i need to get this thing fixed asap.

- jay

 

Sounds very "opti ish" to me. How is it at WOT compared to lower RPMs? Doubt it, but could be something with O2s, if it is all good at WOT then replace those first see what happens. But sounds really like an opti since it is fading in and out with moisture and such

 

sounds like you have bad MAF wiring or an open in your air duct between the MAF and throttle body. take off the duct and inspect it. make sure there are no tears anywhere and check that silencer piece that goes all the way down the middle.

And for the SES light flashing. that just means the PCM is detecting a missfire. But definately the problem lies within the MAF system. wiring, MAF sensor, air duct. A MAF with a glitch will give the engine a hard jerk and just plain run like crap.

Also, disconnect the MAF sensor and take her for a spin. see if the stuttering clears up.

 

i sincerely doubt that it's the opti-spark... i'm relatively certain that the opti-spark would pop up on the Diagnostic Trouble Codes when the car gets put on the diagnostic... besides that, it's not an issue of wet/dry... that's what seemed to trigger it at first, but now it's an all the time type of thing as opposed to an only when it's wet thing. the o2's struck a bell with me at first, and i thought maybe my front o2's had gone bad since the LT header install... but i'm not certain that that's the problem. the problem doesn't correct NOW under WOT... it will catch and move, but it'll just cut out again a few seconds later. with an opti-spark problem, a lot of times, if the car is running like crap, under WOT... it'll accelerate like normal because the computer runs off past memory somehow (correct me if i'm wrong).

JD... that seems to be pretty logical. i hadn't thought about checking the air duct. the thought of the wiring going bad had crossed my mind earlier, and i attempted to inspect the wire but could only physically see so much of it. i don't think the MAF is bad considering that it's brand new, and fortunatley, if it does turn out to be, i can now have it replaced again for free. i will check the air duct tomorrow... i distinctively remember hearing a hissing sound when i was looking at the set-up trying to figure out what the problem was. i'll pull everything off and take a closer look at it to see if i can find the problem. hopefully, it'll be one of those things (preferably not the wiring :/ ), and easily corrected. i would assume that an air leak between the MAF and the TB would create the same type of problems.

one thing that i had thought of was maybe the IAC. i really don't know ANYTHING about the IAC... but i've heard it was the source of another problem i've had... a weird top end surge, not sure if that's what causes the surge, but maybe it's got something to do with this problem too?

i'm gonna check out your suggestions JD... in the meantime, if anyone else has any input, it'd be greatly appreciated. thanx.

- jay

 

Bad opti isnt a code, too bad it isnt though

Air leak could be causing if the maf and map are conflicting, more air than the maf says.

IAC usually have dead spots, or are dead, usually they will always kill at the same point every time, and have trouble idling most of the time.

Still sounds like an opti to me, but symptoms are always different, so hard to say. Optis like to go in and out i know, thats why I suggest that

 

strage that an opti wouldn't throw a code. usually a misfire triggers a code, and usually a bad opti causes a misfire... should set off a multiple cylinder misfire code or something real similar to it. it might not direct you to the opti... but if there aren't any burnt wires or shot plugs, the next place i'd look is at the opti. the downfall to that theory would be if the bad opti didn't create a misfire...

but, to the best of my knowledge, a bad opti does set off a misfire code, even if it doesn't seem like the car is misfiring... and i could very easily see how that relates to the problems that i'm having... but before i go out and spend a small fortune on a new opti... i'm gonna hold out and hope that it's a problem with the MAF or one of the surrounding components.

- jay

 

I agree, but i and two friends of mine had optis go out with no codes to warn, but was still missin like a bitch.

I agree as well with not replacing the opti first, start with cheap or free stuff always.

 

Sounds to me like you have a 12V problem. When ever you get a lot of codes at one time, look at the wiring, the battery and the alternator. This would account for the engine almost dieing as well. It's easy to check. Put a DVM across the battery when the engine is running. Make sure you have over 13V. Also check the cables not just at the battery but also at the positive junction on the passenger fender as well as the ground at the frame and the ground at the engine.

You may also want to check 3 other ground points for the PCM as well.

A questionable connection gets worse in the cold weather. Although I must admit, I don't know anything about the weather in Abilene.

 

right. i have had voltage problems in the past. not sure if my alternator is going bad or battery or what... i know there was a point when i couldn't get my car to start and replaced my battery, which didn't fix it, then put the old one back in and for some reason it started working. i had issues with the voltage for a while, but could never figure out what was wrong... then eventually it just worked itself out, and i forgot all about it.

i don't really know how to go about testing all of that, or fixing whatever problem it is... but that'd be another good route to go if you have any more suggestions on how i should go about it.

i'm also going to check my MAF wiring and my intake elbow to make sure there are no leaks or anything. i'm also thinking about replacing my front o2's with new sensors, as well as putting my o2 sims in in the rear to get rid of all those o2 codes and rich/lean codes. i already replaced the MAF, even tho that still was triggering a code for some odd reason...

my last resort will be the opti, i just really don't think this is the opti... altho i have definitely been wrong in the past...

if you guys or anyone else has any other suggestions or info for me, it's greatly appreciated. thanx guys.

- jay

 

Sounds like you're on the right track. To check your wiring first remove the 2 major grounds at the frame and the engine and clean the connections and the point that they contact real well. check the battery connections to make sure they are clean and shiny. Check the positive cluster on the passenger fender to be sure they are clean and shiny too.

Put a Voltmeter on the battery cables with the engine shut off. It should read at least 12.6V. Then measure from the postive terminal of the battery to a clean spot on the engine. Should be the same reading as before. If not the ground is bad. Now have someone crank the engine. As it is cranking, the voltage across the battery should not drop below 11V. If it drops below 11, either the battery is bad or the starter is.

Now as the engine is running, the voltage across the battery should be well over 13V. If it is not, either the battery or the alternator is bad. Always suspect the battery first, and then have a parts place load test it.

You also want to clean the PCM ground points. I or someone else can give them to you later if you want them. But you have enough to do for now and no need to confuse you with more

Good luck let us know how you make out.

 

I could be wrong but, what about code 16?

 

You can put me on the list of people whose opti threw no code. Nothing at all. I would think a MAF problem would throw a code but I don't know. I would vote opti if it isn't a charging prob.

 

i'm definitely gonna go with the charging problem. the car ran pretty well all yesterday with a few exceptions... and it's only given me **** today once. a bad opti is usually pretty consistent with screwing you up when you're driving.

a friend of mine in town with a 97 WS6 is having the same sort of problems that i am. his MAF went bad, was replaced, and his car is still running like mine. as soon as i get a free chance, i'm gonna check out all of the connections and things like you suggested. any more advice is still appreciated. later.

- jay

 

does youres and your friends car still have the stock cats? how many miles on both cars? i have 94,000 on mine. i had the same problem almost to a t that you are experiencing it it turns out one of my cats are clogged and it caused my car to run like **** one day, run great the next then went back to **** and stayed there till it was like running on three cyls. after so much back pressure from the cat being clogged and the missfire it blew the cat apart on the inside. once it cleared out some it ran fine again. but since it didnt completely clear out it clogged up again. so im ordering a new y-pipe. hope that helps...... BTW i found out it was my cat because very small metal particles were coming out of the tail pipes while it was running, including some of the packing material from inside the cat.....