Well, I have a 99 max. That in itself should explain alot. Well anyway, car is misfiring horribly. Car is shaking very noticably at stops, and during even light acceleration, the car sounds like a old, beaten V8. Not to mention there is an extreme loss of power. During heavier acceleration, I can noticably feel when they all fire, and when they dont. Anyway, I've pulled the coils while the car was running, and they all give a noticably change over the rough idle. My exactly question is, what other than an ignition coil could cause a miss this bad?

BTW: I had the SES light checked, and it's not a cylinder 3 misfire (where it was cylinder 1 a few months ago) and a bad o2 sensor. Could the o2 sensor have something to do with it?

 

I don't know the tune up history of your car but when was the last time you changed your plugs? How many miles are on the car? When last did you change your fuel filter? Other than that I'm thinking engine internals or a feul pressure problem.

 

I have a 95 and mine does something similiar. It misfires at stop. Seems to get worse the hotter the temperature outside becomes. I doesn't misfire very bad while driving although I can feel some hesitation when accelerating at a constant rate. I haven't changed the plugs since I've had the car so that will be my next option. Also I had the CEL come on today which I believe is the KS and an o2.

Why can't cars just be made simple?


WES

 

injectors could cause a misfire.

 

I have a 96 GLE. A few weeks ago, right after I filled my tank, I started getting a misfire on the 6th cylinder. I was trying dry gas, etc to clean it out. I am guessing that the spark plug was loose, because I ended up shooting the spark plug right out of the engine! Needless to say, it stripped the threads and destroyed the coil. I am currently trying to fix the stripped threads. (Any tips or suggestions welcome!)

In addition to everything else, you may want to check to be sure the spark plug isn't loose.

 

do you have UDP?? check plugs and injectors

 

There is a special tool just for fixing that problem. It re-threads hole and a with a vaccum adapter it suck the debris out of hole.

 

if it was stripped then re-threaded, the size wont be the same as it was before.

 

http://www.jatan.net/tsbs/056841.pdf

I have a '99 that had severe misfire problems that were not coil related. After checking every sensor known to man, and everything else too, it turned out to be a broken wire in the harness leading to one of the injectors. There is a technical service bulletin about this, so I think it was a common problem with our cars. Start your car, put on the emergency brake, and put it in drive. Then start pulling and bending the harness. If it is a wire in the harness, and there is an intermitant connection, you will hear the missfire. Good luck......

 

Ya, good point. I see the tool for sale in my tool catalogs I get. About the threads, not sure, because I have not used the tool myself.
Edit... I just read you just screw in a heli-coil.

 

That makes a whole lot of sense. I will check that out A.S.A.P. Injectors crossed my mind, but I just knew it wasnt the coils. I could start it up and the thing would be horrible..turn it off, turn it right back on and wouldnt be a single miss. But thanks, I'm going to go try that now..

 

most likely your injectors. dont try swapping it out. i highly recommend using injector cleaner first then if the problem persists, it may be compression leak so take it to a mechanic or the dealer.

 

Got a heli-coil kit for the threads last night. Re-tapped the hole tonight, Popped in a new plug, temporarily pulled an ignition coil (orig was destroyed by the flying sparkplug) from my 95 Max. Fired it up and it looks like its working good. WooHoo, I now get to drive a 96 GLE instead of a 95 GXE!