Well - i haven't been around here in a while, but i know where to come when i need help...

My dad's 99' has been stumbling a bit at low rpm and throwing a CEL every once in a while but the weird thing is that it runs better when it comes on. He's pretty lazy and hasn't checked the code and i've been at school so it hasn't been checked, but i'm going to pull the code after typing this... I just got back from spring break and he said that on this last tank of gas it has been running poorly and getting worse gas mileage. I drove it last night and it would stumble badly if you try to accelerate in pretty much any gear. Even in neutral - when you rev it, the rpms come up noticeably slower than usual. I also noted that when you try to drive it hard the CEL would flash, but then go off after a few seconds :freak:

I'm thinking it could be the gas or maybe the ignition coils. For some reason i seem to remember the coils not throwing a true code - maybe a "ghost code" or something? I just thought i'd ask if there is something else i should be looking for while checking the codes that's different from the usual.

Thanks for any help... I'll let you know what the codes show.
-matt

 

Well we need the codes. It's a 99 so they are the most prone to having the ignition coils go. When you say stumble do you mean hesitate or shake?

 

flashing CEL means a severe misfire and it is NOT good to drive the car if the CEL is blinking. pull the code. drive it as little as possible.

as for coils throwing a 'ghost code'....if the misfire is a type B (not most severe but severe enough to take note of) it may take 2 trips to set the CEL off.after the ECU detects the code once it will store a soft code (no CEL...what ure refering to as a ghost code) and when it detects it again on the 2nd trip it will change the soft code to a hard code and set the CEL.

 

thanks - code was for cly5 misfire and the one that seems to come and go is for the rear bank o2 sensor.

I replaced the coil and it is much better - no severe misfire. But everyonce in a while while in the low rpms it will hesitate/shake a bit. I put in some injector cleaner and some new gas on top of the half tank that was left.

I guess we'll see if it stops or if i throw a code again...

thanks for all the help.

 

no offense, but injector cleaner the consumer can buy is garbage. how many miles are on the car? if over 100K i highly recommend finding a mechanic that does winn's injector cleaner. its only available to mechanics/shops and costs $25 a bottle or something ridiculous. it takes about and hour and the whole process costs about $120 to have done to your car. if you got some extra cash it is WELL worth the money. i was lucky and my school can get it, and since i pay $30,000 to go there i get to do it for free! i noticed a substantial difference after i did the treatment. smoother idle, a little better mileage, much better acceleration. and i had around 125-130K when i ran it. and i should mention it cleans carbon out of your entire engine not just injectors (although its called injector cleaner....i dont know why haha) and FYI it comes in a little black bottle with a yellow label.

 

i'm not sure that its the prob so i didn't want to go out and spend that kind of cash. If i try a few cheaped things that don't work then i might look into this stuff - what is it called? btw - the car has 114k on it.