The only car I've seen rev up like Christine on it's own was in fact the OPTI...the IAC count increase is just the computer trying to compensate for the additional airflow as the RPM's increased. The car is trying to maintain a specific idle and getting bogus info from the OPTI. Barring any obvious issues like vacuum leaks, bad wires, etc. the OPTI would be my guess.

 

Well, the guy I bought the car from said it might need wires too because he said on rainy days its hard to start. Could this be from the opti and not wires? I'm hoping it's the opti verses the wires only because I saw the wires (well, part of them)... lol... it doesnt look fun. To me it looks like the opti would be easier then doin those damn wires.... I wish I could have known it was the opti (if infact that's what it is) before I did the damn water pump... Looks like it might be comin back off.

 

my car started missing very badly when it rained hard...turned out to be a burnt wire i missed. If it is the opti though, that be a great time for a cam....if the opti doesnt fix it at least you didnt tear the motor apart for nothing.

 

I wouldn't advise that...the additional work for a cam isn't trivial and there's no reason to throw another potential issue into the mix until the original problem is confirmed solved. Everyone seems to have issues adjusting the rockers, and often the car won't even start after a cam swap/rocker adjustment. I'd read the Opti troubleshooting guide first to confirm that's what it is...and stick to only that for now. YMMV...

 

Yeah, definitely. Opti is relativly easy compared to a cam. Sounds like one of those guys who would just throw a cam in and not do springs and rockers and wonder why he snapped the cam. Guess he doesn't know how hard it is to get the CORRECT combo of cam, springs, rockers. Not to mention, I already was bitchen about spending the $250 for the opti... I really don't have the funding right now to spend another 6 or 7 hundred right now on a cam setup.

BTW, whats that you mention of an opti troubleshooting guide?

 

It's posted on here pretty regularly...too many people mis-diagnose the OPTI and replace perfectly good ones, so I was advising you to go through those steps before changing it. I don't know exactly where it is, but do a search and you should find it or someone will likely post it. I think Shoebox or Injuneer created it and it takes you through some basic tests. Based on what you posted so far though, I think it's the OPTI. Could be something simple and easy, so check everything else first (sounds like you've already checked a lot of other stuff though).

 

Havn't checked for the troubleshooting guide yet but I'm about to. I just wanted to mention one potentially huge thing that I might have over looked. There is a tear in my intake elbow, but to me it looked like it still sealed off when the clamp is holding it tight. I read yesterday that a tear in the intake elbow can cause crazy problems. I went ahead and had my friend pick me up a 1le elbow from the dealership he works at. I should have it today if thay have it in stock (large dealership.) Sence I was gonna put the 1le elbow on it anyway, I don't really consider it just throwing a part at it, although to me, it kinda sounds like it might be the problem. Also would explain why it only did it after a few hours of running and not just when it got hot. Maybe it took that long for the rubber to get hot and soft enough to be plyable enough to flex and loose the seal that I thought it had. I hope this is it!!!

 

This sounds all to familiar. My Problem was just like this, problem when heated up. Same deal, cought me by suprise at a red light, idle jumped way up and car learched forward. Stumbled all over the place. Felt like running on 7 cylinders. No code, no ses light. Car sitting for hours, cooled off, ran fine, warmed up, same damn thing.


Here was the solution.....Thanks to Shoebox!!!!!!

click here, go to icm cooling mod.
http://shbox.com/1/4th_gen_tech2.html#ICM_cooling

 

Well they don't have it in stock. I'll have to wait till beggining of this week. The guy at the parts counter didn't even know what the heck I was talking about when I asked for a rubber intake elbow for a 93-94 LT1. I even said the rubber elbow that goes between the TB and the MAF. Now that he figured that out, he still didn't know what I meant by the 1LE. I explained to him that the elbow for cars with the 1LE package didn't have the big long black dong hangin of the bottom. He still had no idea what I was talkin about or what the 1LE package even was. So I ended up having to go to Shoebox's site and get the part number. Well he found it, but he said it mentioned nothing of the 1LE. I told him just order it and I'll be there this week. Some people just shouldn't be in the business they're in.

 

Ya know, I read that and thought about doin it, but didn't think it would be the problem. I'm headed to the garage right now to give it a shot. God I hope this works. I'm about to try everything at this moment.

 

OBDI's do not monitor misfires, only OBDII's do. Thank god. It seems the 2 worst problems to fix are "random misfires" and EGR faults.

As far as testing the opti. Sure you can. You have the 2 feedback signals from the optical sensors. You can view them with a Vantage or other type of O-scope. One person was successful using a multimeter set to AC while monitoring the feedback signals. The high voltage side can be seen with an ignition scope. Viewing each plug with a lead. This will tell you if the problem is from the cap the wire or the plug. Obviously an expensive proposition if you have neither the equipment or the friends that do.

One interesting thing I didn't see discussed was if the problem can be seen sitting in the driveway or does it have to be driven to occur?

I understand the car must be warmed up for the problem to occur.
Correct?
If so, there are a few ignition components that can break down once warm. If that is suspected, a blow dryer can help find the bad component. Warm up one component at a time while the car is dead cold. Warm it to the point of just too hot to touch then try the vehicle. If that didn't exhibit the problem, then move to the next component. The trick is to not let any components warm up OTHER than the one you are testing with the dryer. The only problem components that are solid state and are hard to test this way are the 2 optical sensors in the opti. BUT and this is a big BUT. If the sensor signals where dropping out for any reason, you should get a code. At least 1 of those codes will not illuminate the SES.

 

Re: the intake elbow, definitely fix all the "little things" you can before taking on the Opti.

 

Well, I can't tell if that mod fixed it or not. I han't gotten the RPM's to jump and stubble at idle yet, but maybe I just havn't driven enough after I did the mod. It still does skip and stumble though when I burp the throttle when it's hot. Maybe I had two different problems and I fixed one of them? Who knows. I'll be doing plugs, wires, and putting that 1LE intake elbow on Wednessday. I'm hopping the stumble is just because it needs a tuneup. I don't think plugs or wires have been changing in all of it's 96K miles. Yeah, we got an O-scope at school. I'll try that if it doesn't clear it up.

 

Curious as to the outcome? After doing the mod, did this help with your problem? I know it drove me nuts until I did this mod to correct it. Let me know if it worked, or if you are still having a problem, or found somthing else.

 

Sorry, I forgot to reply and let everyone know how it turned out. By the way, thanks to everyone who offered advise. It DID turn out to be that damn ICM!!!! That mod solved the problem of it idling funny. Didn't solve the misfire, but plug wires did. Got it running like new now!!!!! Thanks again everyone!!!!