car machanics!!!!! anyone???

[twgranger]

I have a problem with the womans car. When it idles their is a missfire. I took it to autozone and they put it on the scanner and it said bad coil, boots,and coil housing. I replaced all that for $150 and the car still runs like crap. The car is a 1998 pontiac sunfire with the 2.4L. I need to know what else could cause this missfire?? I am wasting to much money.:cry: Would a bad o2 sensor did that?

[Jason Hall]

Does It use antifreeze? Does It miss when driving down the road, or does It only miss at an Idle?

[bluevetteguy]

After it idles for while look under the car and see if the exhaust is glowing(only works at night). If it is you've got a fuel injector stuck open, that happened to quite a few of those 2.4s. The injector sticks open and spits fuel down into your pipe and burns off before your cat and screws plugs it up. Hopefully that isn't your problem, just something you might wanna check.
When that happened to my girlfriends car the idiots at autozone gave me those exact same codes.

[Derrick Adams]

I would also look under the hood at night for arcing. If a wire is misfiring sometimes it will show up this way. Nice little electrical dance show under the hood at night! I also had a sparkplug wire rub on the hood of my neon and would short out and miss. Talk about weird, the car ran great when I had the hood up trying to figure out what was wrong, but when I shut the hood to drive it, it started missing! WTF!! lol

[twgranger]

I would also look under the hood at night for arcing. If a wire is misfiring sometimes it will show up this way. Nice little electrical dance show under the hood at night! I also had a sparkplug wire rub on the hood of my neon and would short out and miss. Talk about weird, the car ran great when I had the hood up trying to figure out what was wrong, but when I shut the hood to drive it, it started missing! WTF!! lol
This engine has no plug wires. This is one of them quad 4 engines. The car only misses when it is at idle. How about a map sensor? My brother thinks that might cause it.:wondering

[smackkk]

I would say.....a burnt valve....they mis at idle and stop under acceleration and whn under constant speed....with todays unleaded gas they are more common than they were with leaded gas.

[Jason Hall]

You can run the engine with jumper plug wires & check for cracks In the plastic module cover with a test light. Hook the clamp end to the neg battery terminal & run the tip of the test light along the plastic module cover & the spark will jump to the test light. If It only misses at an Idle You could also have a burnt valve, that will cause the vacume to drop especially at an Idle. The map sensor senses manifold vacume. Have you done a compression check? Checked for vacume leaks at the intake manifold?

[Bill X_R]

If it's a 98' then I would be looking for things that will not cause your engine light to come on! ( I assume the check engine light is not on). I'm not sure whay could be the problem - but if you have a book for the car then I would look down the code list and you could eliminate all of the problems associated with the check engine light.

Just one mans opinion!!


ooloo

[Unclediezel]

anyting after 1996 will turn on a Service soon or Check engine light if the misfire is more than 25 % of the cycles-(REVOLUTIONS OF CRANKSHAFT)

Did you put Plugs in it????----A misfiring spark plug wont mysteriously fix itself--So if you did indeed have a bad Coil-Pak--the plugs must be junk.

Also--as for "CODES" ------ 301, 302, 303, and 304 all indicate a misfire in the respective cylinder--there is ---" NO WAY" --I repeat --"NO WAY" to determine a faulty component based on a misfire Code---That code is stored by the misfire it self --not the root cause------A vacuum leak can cause a misfire--and cause a misfire code-- There is no such thing as a Vacuum leak code--Or a coil code Or a plug fouled code---it ONLY alerts you to a misfire ---not the cause

[PowerTrike]

MAP sensor can definatly affect idle quality. Should be some way to test it with a multimeter...

[grundlegrabber]

If you are sure it's a misfire you are experiencing and not just rough idle, it's likely to be caused by either faulty ignition component or a BAD INJECTOR. We need more info. Need to know what the code is (P0301,P0302, etc). Is the check engine light on? Are you experiencing problem at idle only or while driving, under load, wet conditions, etc? The more specific info you provide, the better your chances of getting an accurate diagnosis.

[twgranger]

It is only at idle when it is missing. It threw some codes but autozone didnt say much except for it was a missfire. When it is ideling you can hear it popping out the exhaust. I replaced both coils, rubber boots for the plugs and the plastic coil housing. It has that dam quad 4 engine in it. It has no plug wires.