So after cleaning the throttle body, changing plugs and pcv valve on my
93 sc2, the car ran great! For about 3 weeks. Then, after
sitting for a week or so, it began to run rough and 1 cylinder is
misfiring. i checked the plugs and they are all still
clean. I have checked most of the obvious things, but haven't yet
had the time to determine what plug is missing.



Is this a common problem, and if so what is the solution? Any
other ideas what to check(i haven't changed plug wires yet but doubt
they would fail suddenly)?



Thanks all!



Rob

 

Sounds like a coil is going bad.

 

Could very well be one of the coil packs. You ask if it's normal. Cars have been misfiring and running rough right from the beginning. From the first time the first car pulled out of the shop. Edited by: sw2cam

 

Well i didn't ask if it was normal, but if there was a common link to
this condition with Saturns. I know it isn't normal, but also
know that it isn't unusual and that there can be many causes - i
wanted(and still want) to know if there is a common reason for this on
1993 SC 2's. Coils that fail frequently, internal problems that
may lead to it, a propensity for going thru plug wires etc.



There is another thread here that asks about oil in the plug
threads. 2 of the 4 plugs had oil in them when i changed
them. My first inclination was that i hadn't torqued the plugs
tight enough and that oil from the valve cover was seeping into one of
the plugs and causing it to miss. Unfortunately, that wasn't the
case. The car is being checked by my mechanic today.
Hopefully he will come up with a cheap/accurate diagnosis.



Thanks all.

 

So it turned out to be a VERY poorly gapped plug, and an O2 sensor - car runs like a champ again.



Thaks guys.



Rob

 

So, I guess your saying you didn't set the gap on your plugs before you installed them. Next time you will. LOL.

 

actually, i did gap them, but apparently i dropped one of the plugs
when it went into the head. or when i put it in it didn't line up
right at first and it bent the electrode.. or something. I don't
remember doing anything like that, but the gap was closed when i peeked
at it. Not surprisingly, it made all the difference on the
world. I have since made a plug installer thingy out of some
hose. The O2 sensor also helped a lot, car runs great.

 

Glad to hear you got it figured out and running again.

 

An old sparkplug boot makes for a great sparkplug holder/starter. It all comes down to running.........and you got it running. Edited by: sw2cam

 

I also changed the coolant temp sensor - really, that made all the difference. It was a 15 minute job once i got the battery off. $11 at NAPA.

This is the best the car has run since i have owned it.

Thanks to all who have helped commented.

Rob