Ok guys so this might be a little long im sorry just trying to get all the details down. So im in Columbia, SC and i just bought a used 95 pontiac trans am. It has 121,000 miles on it, 6-speed manual, 5.7L engine, all stock. Well i bought it with oil leaks and they turned out to be worse than i thought so i had to reseal pretty much the whole front of the engine from the o-ring seal to the camshaft seal, etc. That took care of the oil leaks. Well then it started to overheat so i replaced the water pump. Problems solved. Then a spark plug came loose. No prob. Well 24 hours after getting it out of the shop from the resealing i break down. Now they say i need a new wire harness. No prob. So now i’ve put $2,000 into the car (thats including new tires). SO ONCE AGAIN WITHIN 24 HOURS OF LEAVING THE SHOP i break down again. So I take it to a different shop again to get a diagnostic. They won’t be able to tell me anything until monday but they put on a new air intake boot (without my permission because mine was taped to secure it better and i knew it wasn’t leaking air) and it cut off on them again in the shop (so i’m not paying for the boot). When i break down it happens unexpectedly just like i’ve run out of gas. Well once there was almost like a split second of a lurch but other than that its always been a smooth break down. No bad sounds or anything. And the motor sounds great and the car runs really well until it just stops… Then if i let it sit for a little while it will start back up and go for a little then stop again. No one can really tell me whats wrong with it. My fuel pump seems to be fine. alternator seems fine (my lights dont dim or anything). Distributor maybe? Or could it be the fuel filter? And isn’t there something i can do about the shop? Wouldn’t a prudent shop at least run the computer on the car? I don’t think they did because at the shop where it is now they said that 6 codes popped up on it. So they want to erase them all and run the car and see which ones come back up. So can’t i take the other shop to court for neglect in their work? I mean breaking down TWICE WITHIN 24 hours of leaving them. And then the rest of the afternoon they wouldn’t even pick up the phone 
Did they say what was wrong that you needed a new wire harness, specifically? Did they give you the engine codes and can you post them here. It sounds like this shop is chaseing ghosts. In cars this can happen when the wires do not give good data to the computer like they should. It is also a way to stick you with a big bill. The trouble with restarting and running again is that the trouble goes away. That means that most of the time all the data runs good. Did they mention a crankshaft sensor? Bad wires to the sensor or a bad sensor will turn the engine off in a heartbeat.
They said that the wire harness looked like it had been burned. They said that maybe when i was leaking all the coolant it could have dropped there and then been scorched. But after i left and thought about it i dont even think that that’s possible. i forgot to write the codes down but i will get it from them tomorrow. No we havent looked at the crankshaft sensor. But i did ask them about the o2 sensor.
You are describing someone throwing parts at a problem without taking the trouble to diagnose anything. They’ll continue to do this as long as you’re willing to pay them to do it.
This isn’t that difficult a problem to diagnose. When the engine dies and won’t restart you (or someone) needs to simply check to see if the engine has fuel pressure and ignition spark. One or the other will be almost surely missing. Then that specific problem can be troubleshot.
Throwing parts at a problem is just guesswork, and that will get very expensive very quickly.
Ya i know tell me about it. It’ll restart and run a little depending on how long it’s been sitting. If it sits overnight it’ll make it a couple miles but if it only sits for like 10 minutes it’ll make it about 200 feet. And the guesswork is why i have taken it to a new shop. The fuel pressure is fine, there might now be a spark. But everyone seems to say its electrical???
This car has a coil. this sounds like a classic coil failure. No spark when hot, runs again when the coil cools down.
hmm. now that’s a new one (next to the ICM assembly??) and if it’s something that simple it irritates me that those airheads at the shop miss it.
Whether it’s the coil or in fact fuel pressure can only be determined by TROUBLESHOOTING. Find out if it is missing either spark or fuel when it won’t run.
It’s the only way to cure your problem without just replacing everything that comes to mind.
And what if its my Optispark?? Those are ridiculously expensive to replace. Is there anyway to cut down the cost of that? I also heard something about upgrading it and completely taking it out.
It’s getting fuel
You’ve said before that your fuel pump seems fine, and you’re saying that it’s getting fuel, but unless you’ve actually measured the fuel pressure when the engine won’t run you can’t know that for sure.
And if it’s your ignition then that’s what needs to be repaired / replaced. Junkyards / recyclers can be a pretty good source for stuff like that, and it really shouldn’t be that expensive, it’s close to 20 years old.
So i guess ill get that pressure checked out after it cuts of. And one of the shops wanted $700 for a distributor so i found one for $100 with a warranty but the other shop wont install it unless the warranty covers them too and even then want $300-400 for installation. I did some research in case it comes down to that.
Oh and with the LT1 engines the 95s didnt come with a crankshaft sensor so thats definitly not the problem
$300 - $400 to install a distributor seems very high.
Ya i know and it’s very frustrating because i don’t feel like these people are taking me seriously when i’m a female and walk into the shops alone. And I guess they’re just mad that i don’t want to buy the distributor from them for $600-700.
Yes, the first thing to do would be to check the fuel pressure check valve and pump, it sounds like this isn’t your problem since you make it further when it sits overnight, but nevertheless you have to leave the car somewhere that is willing to have it for several days, and watch fuel pressure over the course of at least one day, hot and cold.
My trans am had a problem with the Ignition coil fuses (there are 2, one for each side) that kept jimmying themselves loose and making me lose power, if they both fail, it would stall. Check the fuses and the wires going from them to the coil, or rig a new wire to see if it still occurs. You would know if any of the wires are bad because they would test with too high of resistance.
The only way to know if the wiring or ECM is bad is if you monitor voltage TO the coil while its running, if it loses power every time the car dies that narrows your choices, but if it maintains voltage than its probably the coil. BUT, if you had a problem with spark plugs/wires coming loose, then it is probably safe to say that poor connection probably killed the coil.
When mine had similar issues I took it in and it turned out to be about 5 different codes mostly vacuum leaks and ignition, new fuel filter, and new air filter. One code they couldn’t fix was the distributor (optispark) code. But it ran fine for a few days, now it is starting to act up at certain times but there’s no pattern its pretty intermittent.
I’m pretty sure the optispark is on the way out. But we shall see. Hope it helps.
Did u buy car from private party? Sometimes u can go back to seller and get some info on previous repairs. U never said how bad ur oil leak was. U bought car with leak so it must not have been huge? The chevy small block was unchanged forever and than the lt1 showed up with some different front engine tin and than the ls1 changed a Bunch more. An “oil leak” is all labor for shop. Lots of tear down and reassembly. Will engine even idle now?
So my oil leaks were pretty horrible (camshaft seal, o-ring seal, oil pan and another place i believe) the whole underneath of my car was covered in oil for days. but all the oil leaks have been cleared up. the car cranks and then turns off after a little while. I’m hoping its not the optispark because as with the oil leaks its all labor for not that difficult of a task. I’m trying to get the shop to monitor my fuel pressure and check my wires and coils but they’re not doing to good of a job (didn’t even pop my hood today) so that mean another day on hold…
Oh and the dealer i bought it from tried to give me the wrong carfax on it so i got him to knock $2000 off the price with that and the leaks…