Hi everyone...I'm new and already fed up with my bird, hehe. I've been having a lot of problems with misfiring since I bought her in April last year. Three days after I bought her, she was misfiring, my service engine light was blinking during acceleration. I was dumb enough that I honestly didn't know what a darn misfire was. I'm learning a lot however. I took the car in to the dealership where I bought it and they ran a test, said one of the coils was burnt out, and they changed it out and the spark plugs as well as a courtesy. 50 miles down the road, and the light comes on again. No misfire this time, just the solid light. I called around, did some reading and realized it could be my catalytic converter. Got another diagnostics run, and it was. Luckily, my car was still under the 80K mile mark, so I got my cat replaced for free at the Pontiac dealership. The guy told me to drive easy to let it "burn in" and so I did. Well, to this day, it still sounds like someone's rattling rocks around in a tin can when the engine is revved up. I don't know why, but I still have another warranty on the new cat if for some reason it was installed wrong. Either way (I'm blabbing like a typical woman)...recently, I had a problem with the misfiring again, it sounds good in park at idle, but as soon as I put it into any other gear it feels like the whole car drops two inches lower and shakes pretty heavily, like it's preparing to throw up. At this point, the light starts flashing, and while accelerating no matter the rpms, it's flashing. Sometimes it'll level out while driving between 55 and 60 mph and the light will be only solid. But eventually flashes again when I slow down or accelerate again. Now, a few weeks ago, I changed out my sparkplug wires myself under supervision, and as soon as I did, it ran great for about a week. Then it started misfiring again. So I changed my sparkplugs. Got Bosch Platinum +2...the double pronged plugs? and changed those out. Had someone check to make sure I did it right. And the problem has only gotten worse. What next guys? The coils? Or could it be the fuel injection or cat again? I'm so lost and so new to this. All help appreciated.

 

Not really any idea...

But I will say this, if the MIL is flashing, it means there is something terribly wrong that will impact your engine/emissions/etc. READ burn it up. So, if you have a misfire, the MIL is flashing, it's telling you to stop ASAP and get it fixed or something (CAT or?) is going to be fried.

A solid MIL is just a caution light, telling you that the system has reported a failure that should be addressed.

 

If the check engine light is on-read the code. Could be anything. Bad gas, any plug wires burned or not tight? Did you gap the plugs--NGKTR55s are one of the best plugs to use for Ls1 but don't know what you have. When you pulled your old plugs-what did they look like-fouled or anything? Need more information. Rocks in a tin can can be the motor cutting back on the timing from Detonation. What year car are we talking about v6 or v8?

 

Bring the car somewhere that will read codes for free, like auto zone. Don't worry about the description - just write down the code(s) and post them.

 

Sorry, I left out the model...it's a 2002 Firebird 3.8L V6...so dumb...lol

 

I'll stop by autozone one night this week. Someone mentioned me burning something up so I've got a friend to get me to and from work till I get the time to get this checked out. I have a warranty for the next 35000 miles, so I'll be taking it in Monday to get it looked at either way. $100 deductible isn't so bad for a complete engine/transmission rebuild if it needs it. I've got it covered hopefully. Thanks for the help...any more suggestions and advice is welcome. I'm trying to soak up as much info as I can.

 

Flashing light is no good. Solid is ok. Most warranties will cover a tow if it's necessary. Flashing light to me is necessary.

 

Didn't answer any of my questions. Can't help if we don't know. Just take it in to get looked at if you have a warrenty and don't pay a deductable till the damn thing is fixed!!!!! Don't waste $$$ or time doing anything to it.

 

I had a terrible misfire on my freshly built 383. Everything was new - plugs, wires, engine, etc. Tried all that I could think of - changed plugs, coils, wires, check crank sensor, cam sensor, injectors, etc.

Finally, it turned out to be a plugged catalytic converter. Passenger side was completely plugged. Gutted it - runs great now.

 

did you check all the coils? dont use bosch plugs btw, especially platinum.... they are junk and overpriced. NGK is the way to go, cheap and work great.

check all the coils, and change out your plugs to the correctly gapped NGK's and see if that fixes your problem

 

I went to autozone today as it was the first chance i got, and the guy got the code P0305, misfire on cylinder 5. I think when I changed my sparkplugs, perhaps the wires are touching. Could that create a charge between them to make it misfire? Maybe that's a stupid question. But, I'll go and get the other recommended plugs and have those changed out. The 'expensive' ones weren't that expensive, so I'm assuming the cheaper ones shouldn't be any more than pocket change. Thanks! I'm going to re-run the wires tomorrow to make sure they're not crossing, and if that doesn't solve it, I'll get another reading and see if it gives any other codes, such as the catalytic converter. I know if the cat is defective long enough it can burn the coils out, so I'll check those two things next. Thanks again.

 

PS-How DO you check the coils?

 

its a solid light now right? did you replace your wires yet or look to see if there is any moisture or rust in the boot? and to check the coil you would have to get an ohm meter and check the secondary resistance and check the primary side. Before you do that i would switch that spark plug with another cylinder and see if that one starts to miss.

3800 engine- primary resistance .3-.6 ohms

secondary 5,000-6,500 ohms

 

i did go and get some new plugs today...the ngk brand ones you recommended. Going to get them changed out as soon as i finish my laundry and get to my friend's house. He's the one with the tools. I'm going to check the wires for touching or crossing each other. When I got to autozone yesterday, I opened the hood and it looks like they are all touching, perhaps we should have pulled them tighter and away from each other before we put them in the clips that keep them separated. So I'll do that as I couldn't do it yesterday when the engine was hot. And is the boot the part that goes into the engine on the sparkplug? Or the part that goes into the coils on top of the engine? I'm still learning here.

 

the boot is the piece that connects to the plug or the coil. and to avoid confusion lable or do one plug at a time to not put the wire on the wrong one. not insulting i just now how it is

 

No...I don't take any of this as an insult at all. There are a lot of guys I've met recently that don't know how to change their own oil...and I try my hardest not to sound condescending to them simply because I learned when I had to. Anyways...I fell asleep yesterday and am going to get this done tonight as I've had way too much sleep, hehe. I am going to try running it in the dark to see if I see any sparks, then literally run down the list I've made of things to try that you all have recommended. I'll update you all tomorrow. Thanks!

 

be carefull when you do that because that spark will hit you good.

pm sent

 

I wasn't going to feel around for a spark, lol. Simply see if I can see one visibly in the dark that could explain a loose end or crossfire. My boyfriend reached in while the car was running and simply touched the wires to make sure they were in all the way, and they shocked him. That's why I bought new wires. Maybe I need the expensive wires and the cheap plugs? I paid $40 for the wires at Autozone. It's all they had in stock. I didn't know any different.

 

If you have no luck with plugs, wires or coil, I would check your fuel pressure.

 

I have ran MSD plug wires/ NGK spark plugs for years with no problems, so if those don't fix it, next would be to check for proper fuel pressure. Did you get the codes scanned? If so, let us know what they are.