Alright i have a 98 cavalier with a 2.2 and i am have a weird misfire problem. It only happens when the engine is warmed up. After about 15 minutes of driving i get the flashing CEL and the car starts to run like crap. I have no power and it's a constant misfire throughout the powerband. I limp the car back home and the next day i start it up cold and it runs fine. I drive it again and the same thing happens. Any ideas on what it can be. I had a problem with plug wires with another cavalier before but the car would only studder at a certain rpm. Any help?
check your plugs, wires, fuel filter, and other tune up items. if you can get it to idle while its missfiring, pull the plug wires off and reattach them one at a time to see which cylinder is missfiring, then you have a starting point for diagnoses.
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Id pull the plugs and see what they look like, and go from there.
Id also get the CEL checked, its free at autozone and other places. (there is a code for each cyl when it misfires, unless its all of them itll be "random cyl misfire")
Those would be my 2 starting points.
"A car just isn't a car without a little blood, sweat, and beers." -- Shadowfire
Primary cause of missfiring when an engine gets warmed up is a bad ignition coil....
When they're cold they work, when they get hot their windings start shorting out...
Leland Sparks wrote:Primary cause of missfiring when an engine gets warmed up is a bad ignition coil....
When they're cold they work, when they get hot their windings start shorting out...
Thanks, that's the answer i was looking for. I have another cavalier so i'll swap coils and see if it works.
Alright, i swapped the coils and plug wires from my other car and i still have this problem. Sucks because the one car is a 97 and replacing coils is not fun. Anyway i scanned the cel with my reader and i have the following.
P0141 o2 sensor. I replaced it with a new one
P0300 This is for the random multiple cylinder misfire.
P0172 System too rich Bank 1
Now is the P0172 code the cause of my problems? Any ideas to what is responsible for this code?
A cold engine requires a richer fuel mix, and, as the engine warms, this
air / fuel ratio ... (less gas, more air) ... is called for.
Our Cavaliers are known for their fuel injectors failing.....
Can anyone recall if their injectors could be causing this ?
Could this be a some kind of sensor problem?
Still can't figure out what is wrong? Anyone else?
Check the wiring on the injector plug. Could have come apart. I found this on a buddy's car. Pull the connector off and tape and look at the electrical connection/connector. On my friends car the the little metal connector was almost pulled out of the plug. Pushed it back into place and everything is fine now.
Mike Macie wrote:Alright, i swapped the coils and plug wires from my other car and i still have this problem. Sucks because the one car is a 97 and replacing coils is not fun. Anyway i scanned the cel with my reader and i have the following.
P0141 o2 sensor. I replaced it with a new one
P0300 This is for the random multiple cylinder misfire.
P0172 System too rich Bank 1
Now is the P0172 code the cause of my problems? Any ideas to what is responsible for this code?
sounds to me that the P0141 is causing the P0300 and P0172... if the o2 sensor is bad it can send the computer a false reading giving it more fuel... so maybe its sending the signal for the right amount of fuel when the cars cold... but when its warm its just sending the signal for the same amount of fuel as when its cold... as it heats up it should gradually send a signal to give the engine less fuel...
so by giving the engine more fuel then it needs when its hot your going to end up with a misfire... which would be your P0300 code... and your P0172 code... because its getting to much fuel...
the flashing check engine light means its catalyst damaging... meaning your dumping raw fuel into the catalytic converter... and thats not good for it... that can cause the cat to fail quite quickly...
so my bet is on one of the o2 sensors is screwed... you didnt say which sensor you changed... the pre-cat o2... which will be the one before the cat... or the post-cat o2... which would be the one after the cat...
the actual explanations for the codes your car brought up are...
P0141 - Oxygen sensor heater circuit, heater current above or below threshold
P0300 - Engine misfire detected by PCM
P0172 - PCM detects an excessively rich condition
my money is for one of the o2's... that code isnt o2 specific... so youd have to get a obd2 scanner and have a look...
hope this helped you out a bit...
