: engine miss



PhillyCaddy
09-07-03, 06:00 PM
i have a 94 sls that all of a sudden started having a minor engine miss. it seems to happen around 1-2 thousand rpm range the most. i have replaced the wires and the plugs are new. i have checked the coil towers and they seem to be fireing fine. if i drive the city i can realy feel it but on the highway it clears up or if it does happen i can punch it and it clears up untill i get down to slower speeds. any idea's

AKPsiMC03
09-07-03, 06:34 PM
my only guess would be that one or 2 of the plugs may be gapped wrong.

PhillyCaddy
09-07-03, 06:35 PM
i did double check the gap on the plugs

PhillyCaddy
09-07-03, 06:37 PM
i just bought it a month ago and ran it about 800 miles with no signs of any trouble and all of a sudden this happened.

ljklaiber
09-07-03, 07:04 PM
Remove the cover over the intake valley. At the rear you will find the fuelpressure regulator with a vac hose . Remove the hose with engine running. If you see fuel leaking or squirting. That is the problem. (i.e) too much fuel at low rpm. If all is dry with vac hose removed. Check elsewhere., but I had the same problem when I bought my sls used and hi mile. Hope this helps.
75 bucks for part and time to replace less than 5 minutes.

PhillyCaddy
09-07-03, 07:31 PM
i will look in the morning thank you

PhillyCaddy
09-11-03, 10:15 PM
ok not having fun. it is not anything to do with fuel. checked
the system out and are now back at a electrical problem. has
anyone had this problem. could it be either a cam or crank sensor or the ignition module........ ANY IDEAS

Katshot
09-11-03, 10:51 PM
You can guess all day or you can throw it on a scope and "see" if it's even an actual ignition issue or not. There's a lot of things that can cause those symptoms. Could be anything from an ignition cable to a coil, to an injector, to a bad head gasket, weak lifter, valve spring...........this could go on.

A747BLDR
09-14-03, 12:54 PM
I had the same problem with my car.
This problem was caused by clogged egr ports under the intake manifold.
I removed the intake and scraped all the carbon off the egr passages, reassembled engine, and roadtested. Hesitation/vibration gone.
I'm sure this may be covered in other posts on this forum, but I didn't think it was applicable to this situation. Dealer wants over $400 to do this job but I did it in about 2.5 hours. It was well worth it. If you suspect this is your problem, unplug the egr valve and road test. If hesitation is gone, you have clogged egr ports.
Hope this helps someone.


ok not having fun. it is not anything to do with fuel. checked
the system out and are now back at a electrical problem. has
anyone had this problem. could it be either a cam or crank sensor or the ignition module........ ANY IDEAS

4T-80E
09-15-03, 05:34 PM
Hi, I'm new to the forum just wanted to mention that carbon tracking on the plugs could cause this. Pull all the wires out of the valve cover and inspect the hole where the spark plug fits into the boot. If you see small lines (graphite colored)running parallel with the boot you have found the source of your concern. New plugs and wires are a must.

4T-80E
09-15-03, 05:41 PM
My bad ,didn't fully read the original posting. One question though. Did you install the small plastic wire holder near the coil pack? It holds #2,4,6,8 plug wires. I've seen this little guy get carbon tracking on it, causing a miss and sometimes a stalling concern.Ever since I got bit I don't install that holder when I replace wires. Just a thought.