check engine can't make up it's mind...
 

So I'm having more and more issues with my 2000 trans am...

So now our issue is that every few hours the check engine light will come on with a p0300 code (multiple cylinder misfire) when there's no misfire... so for a few hours the light will stay on and then turn off and then maybe another day later it'll turn back on and turn off... and I can't figure for the life of me what it is, the sheet from autozone said it could be like 7 different things (spark plugs bad o2 sensor vacuum hose leaks etc)

Anyone happen to know a way to narrow this issue down or will it just be a replace everything until it goes away kind of thing? I bought plugs two days ago on discount from rockauto and will have them in on sunday..

Thanks again!
-Luke

Whats done to your car mod wise?

Tune up records?

Yup. Sounds like a miss that's clearing itself.

Start with the basics, like the plugs and wires.

if u have MSD coils, throw them out.

I once had an injector that wasn't fully seated, and a spark plug wire that wasn't fully clicked into place. Didn't have that code, but I'd start there, make sure everything is firmly in place.

my brother had the same thing happen to him on his jeep the check engine light was on then he would get it reset then drive a few weeks and the check engine light was back on it was a bad coil pack and the jeep still ran good

I don't remember the specifics on the LS1 setup but the crank position sensor could be getting bad readings. Does the engine sound any different when the check engine light starts to flash before it goes on solid? When it's flashing is when the actual "misfire" is occuring and it will often show a specific cylinder code at that point in time. My old 96 SS would do it all the time and the car ran perfectly fine. I replaced plugs, wires, coil, ignition module and it still would happen randomly with no affect on the way the car ran. But starting with the basics like plugs and wires is a good idea.

No mods on the car at all, And when the light's flashing saying I have a miss it dosen't have one, and it still comes up as a 300 code (which won't specify a cylinder) Like I said the plugs came in about 20 minutes ago so I was gonna do them today but it's cold as hell so maybe tomorrow, then I guess I'll just have to start taking things apart, I'll probably take off the fuel rails and clean them, then I'll check the injectors, then the coil and ignition module lol.. what a nightmare this car has been since I got it lol... :facepalm:

How many miles? What has been done tune up wise? Do you have access to a scanner to read fuel trims and whatnot?

Stupid question, but what plugs are you putting in it? They can make a difference.

Case in point, my 1996 V6 uses iridium plugs, and only iridium, but when I first got the car and did a tune up on it, I put Bosch +4 ( total junk after a couple thousand miles) and they are platinum based. That code would come up. I put AC platinums in it, same deal. It wasent until I found out that Iridium was O.E. I popped AC iridiums in it, never got the code again.

I don't think I have access to a scanner that can do fuel reads, and I'm putting in bosch platinums, didn't really think iridium was worth $7 a plug, it's 113k miles and I don't know what's been done as far as a tune up seeing as I just bought it two months ago... I've gone through the service records and haven't seen anything about a tune up, so I wouldn't be surprised if there wasn't one done.. Should I just return my plugs and get some Iridiums? lol..

Do yourself a favor, return those plugs. They're only decent in European vehicles. You get what you pay for. though Bosch is saying on my computer that platinum is O.E. from them, Autolite and AC is saying iridium. AC's part # is 41-110, go with those, you'll be fine and won't have a problem 5K miles later.

Get NGK TR5's for your car and a set new wires.

Already have the new wires I'll just get better plugs.

Were you planning on coming to the meet next weekend at the Firkin Tavern? I have a Diablosport hand held which can scan a lot of stuff and I'll be there.

I have work next weekend 8-4 :-/ lol. Thanks though dude.