1993 Saturn SL2 intermittent SES light.

My 1993 Saturn SL2 has been giving me weird problems lately. Awhile back, it
was fine up until I tried starting it. Once started, the exhaust
system/engine would vibrate very badly. Like it was misfiring, but that
didn't seem to be the root cause. Someone said I might have had bad gas, so
I refilled and still had the issue. I tried fuel injector cleaner and
reseating everything related to fuel/engine. Eventually I made the mistake
of going to get my car's diagnostic codes read(by a dealer, when I should
have went to Autozone). At this time the problem was somewhat self
resolving, yet the pesky SES(service engine soon) light would not go away.
They told me the car was throwing different codes at them, and they could not
pin point what it may be. Ever since then, I get the SES light after driving
for a little while, it goes away when I go really fast(around 90), and also
when I decelerate and stop it often goes away. The damn thing has been so
sporadic that I could only pinpoint it down to those times, but of course,
the times vary. Any help or comments are greatly appreciated.

 

Remove and replace the 4 spark plugs with properly gapped OEM ones, then
replace the 4 spark plug wires with OEM as well, being careful to route them
exactly as they were originally. Then clean your throttle body using a
toothbrush, clean rag, and throttle body cleaner available at any automotive
store. Replace your air filter, and the fuel filter too if is been more
than 30K miles or so since it was last done. Check for vacuum lines that
are cracked or not on correctly and fix if needed. You can also replace the
PCV if it has not been done lately either.

Then drive and see if the SES light stays out. If not, then have the code
read free at AutoZone. I'd guess it is your EGR if it has never been
replaced. Another frequent issue with this engine is the Coolant
Temperature Sender (CTS) so this could also be setting a code and causing a
rough idle. Both are very easy to replace.

By the way, in the future, when you post, it is extremely helpful to include
basic essential information, such as mileage and maintenance history. It
would allow readers to give more focused and hopefully better advice.

Good luck

Bob

 

sounds like the EGR valve is a good place to start. Replace the
solenoid that controls it as well at the same time. James