engine misfire at cruising speed

[postmessage]

my engine misfire while accelerating at around 2000-3000 rpm. engine runs fine on idle. also runs fine when im at cruising speed at 4000 or above rpm. anyone out there know why and how to this problem? oh and my car is 96 sl2 with 98k miles.

[saturnspeed_12]

ok are we talking automatic or manual? also does it seem to happen at a load, like it/you shift and try to get going? does it really seem to happen on a hill at those rpms? if so id look to new spark plug wires. but it could be numerous things, like cts, spark plugs, bad injector, oil leak in cylinder or on spark plug. really if nothing has been replaced then get new wires(either napa belden, dealer, or msd), spark plugs(ac delco rapidfire, ngk dont do nearly as good), cts(dealer), and check for oil around spark plugs before pulling them. then check for oil on plugs, you should be able to tell if there is, its normally black but kinda glossy looking, thick not thin. and if oil is in the plug hole then dont be fooled by oil that drips on it when you pull it. also if you are having problems with lost oil, put marvel mystery oil down on the piston, just enough to pool, and let it set for 24 hours but keep checking on it because if drains down within 8-12 hours(normally will) then add some more.

[molded]

Originally Posted by postmessage

my engine misfire while accelerating at around 2000-3000 rpm. engine runs fine on idle. also runs fine when im at cruising speed at 4000 or above rpm. anyone out there know why and how to this problem? oh and my car is 96 sl2 with 98k miles.

if you havent fixed your problem maybe your sparkplugs could be bad. try to re-gap them smaller than .040 inch. set them to like .030 or .025 inch. ive done this before and i know it works. misfire problem dissappeared.

[macexperts]

make sure you're using Saturn plugs or NGK (saturn sells these actually)

and not platinum which have known issues



also you might want to check wires for resistance and see if they're corroding
i had a set that looked perfect, did a resistance check with voltmeter they tested fine but then one day i pulled on one and it was corroded inside and fellapart

coil packs could be failing as well but i'd worry with that last

[saturnspeed_12]

there wont be any issues with platinums if you get a good set, and actually know how to gap a platinum plug.

[peppermrj]

Originally Posted by postmessage

my engine misfire while accelerating at around 2000-3000 rpm. engine runs fine on idle. also runs fine when im at cruising speed at 4000 or above rpm. anyone out there know why and how to this problem? oh and my car is 96 sl2 with 98k miles.

I would also suspect plugs/wires. NGKs are the factory plug and highly recommended. I used AC delcoes last time on my 96. There was some discrepancy as far as the proper gap. The owners manual called for 60 thou while the underhood sticker said 40 thou. I went with 40 and was glad. There was a TSB out from saturn recinding the 60 thou spec.
Good luck and let us know what works.