My car is currently being a royal Bitc#. For some reason it likes to missfire or what I think is missfiring. At low rpm's I hear a popping sound like small explosions coming from my engine bay. That's missfiring right? When the fuel hasn't fully combusted in the cylinder and the remaining gas combusts in the exhaust. Probably my headers. Well it only seems to do this when the engine is cold. It's really bad in the morning when it's been sitting all night. It is not, my distributor cap, rotor, spark plugs, plug wires, or O2 sensor. As I've already replaced these. I'm going to be taking it into a chevorlette service center tomorrow to do a diagnostics check because I have no idea what's wrong. If anybody knows what's going on with my car please let me know. I'd rather not have to pay the service center $85 just to tell me I need to replace this or that which will cost me another but load of money. Well thanks to anyone who can help, as I am most desperate at the moment. I'm trying to make this thing a decent street machine not something I get used to seeing the back end of as I'm pushing the car to the side of the road. Thanks alot.

 

You mention headers. It might be a gasket leaking. Hard to say. If the shop can tell you for sure what the problem is then it is money well spent.

 

Isit a misfire or does your your car kinda spit and sputter. If is a misfire it sound like something to do with the timing if it is coming from under the hood and not out the exhaust but I cant tell you for sure with out being there. Im not sure what could cause your timing to get out of whack. Sorry I couldnt be more help John

 

I don't know what you mean by spit and sputter. The car lags in performance when it happens and you can hear these small pops comming from withen the engine bay. The car also has to be moving for this to take place. When just sitting still and hitting the gas it doesn't make the popping sound but sometimes when leaving it idling, the rpm's will drop really low and the car will stall. They did a small check on it I guess today but couldn't figure out what was wrong. Obviously they did what most mechanic's do. Turn on the car pop the hood and play with the throttle from underneath the hood. They didn't drive it around. The sheet says "scan and check operation of EFI, Fuel and IGN. systems. Roadtest to check. Need addition time to perform diagnostics for engine misfire." This is very frustating to not know what's wrong with my car. They're going to check it more on tuesday but that's awhile from now. I hate driving around with this thing missfiring all the time because I have to peel out practically at every light for it not to happen. Well please post any more suggestions you might have. Thanks alot.

 

I guess your not getting any codes. My car does something similar to what yours does but only if the service engine light is on, when it is off the car runs like a new one. It sounds like it has something to do with the ignition, timing or coil. You might try doing a tune up on it if you have not already performed one(cap,rotor,wires.and plugs).You can pull the cap up and make sure that the terminals are clean and the cap doesn't have any cracks in it (sometimes there can be a crack that you usually can not see with the naked eyes letting in moisture and cause misfire untill the car gets warmed up to operating temps), I would at least replace the cap and rotor (the ones with the brass terminals last longer and don't get that white build up as bad) they are fairly inexpensive. You might get the coil checked out or try to put a known good one on. I've heard that coils are either good or bad but I've had coil gives me problems. I hope some of this might help you in you situation. I can only tell you things that I would do in your situation. It is hard to give you really good advice without seeing or hearing what it is doing first hand. John

 

One step ahead of you man. The plugs, wires, O2 sensor, cap and rotor have all been replaced. I've never messed with the coil though, I'll have to take a look at it. Any other advice I know it is hard to give ideas when you're not there to witness the problem. That's probably why the mechanic couldn't find anything he didn't realize that the car had to be moving to really witness the problem. Well thanks for the advice.

 

I was just reading the failed emission again in this forum and Christobal was talking about a vaccum leak causing a lean mixture causing misfire. You might want to check for leaks. John

 

How do you check for leaks? Do you mean general oil leaks or something else. I do think that my oil is leaking but very slowly. It's not even leaving drops on the ground and don't you think that this is something they would've checked for today when they did part of their diagnostics check. If they even did it.

 

not an oil leak a vaccumm leak.yea im assuming they would have checke for vaccuum leaks at the shop but you you never can tell with some shops. You can start your engine and spray carb cleaner all around the top of the engine and if you have any change in engine rpm that should be where your vacumm leak is. pay clos att. to where you are spraying it so you can pinpoint where the leak is . you might want to go over to the ( Failed emmissions Again) in this forum and read it can give you a better understanding cause I'm a slow typer and it would probably take me all night to try and type what is in that thread. Alot of good info in that thread

88droptop Wrote"BY THE WAY I CHECKED FOR VACUUM LEAKS. I CANT FIND ANY. I SPRAYED CARB CLEANER (CAR RUNNING OBVIOUSLY) ALL AROUND INTAKE TUNED PORT RUNNERS, CHECKED LINES, NO LEAK I CAN FIND."

 

Sorry in a rush, and didn't read everything. I'd say pull all the plug wires eventhough they're new, you have headers. I've burned up many of wires in the past and traced my problems back to them.

symptoms, hesitation on acceleration, backfiring, sputtering.

 

Doesn't every car have headers. They're still the stock one's sorry for the confusion. Also these wires are well heat shielded and I've looked at them many times. I don't see anything that shows it being burnt. Plus, this happened before I replaced the wires.