2001 sc1 Cyl 1 misfire

my wife's 2001 sc1 is idleing very fast, 1800 rpm, and using my
brother's obdm2 computer, I got a "cylinder 1 misfire". Anyone got a
clue for me to follow before I take it in?

 

Your really do not provide enough description of any other related symptoms
to make a diagnosis, but if you want an educated guess, mine would be the
Coolant Temperature Sensor since these are known to fail and when they do
they cause the engine to run rich. This is a cheap part (~$10) and takes
about 5 minutes to swap out. Other possibilities include a vacuum leak
possibly from a cracked hose or a severely clogged air filter. Good luck.

Bob

 

My wife's 2000 SL1 has the same thing I think.....runs fine, then put
in 'park' and idle jumps to 1800-2000. Does not always behave like
this though--only sometimes.
Also, some sputtering noises out tail pipe (usually in idle).
Some days 'check engine' light is on & other days it's not. Had this
checked and got the same code (301).

Also I don't know if this is related, but, car sometimes shifts VERY,
VERY hard into reverse. This is not just when idling high.....normal/
low idle....1-2 second pause after shifting....then shifts hard. This
problem started before the idling problem.

Any help or advice is GREATLY appreciated!!!!
-Phil

 

Yes, I also have some exhaust sputtering. I have so far regarded it as
an isolated issue, unrelated to my before mentioned problem, but maybe
it's part of the problem.

 

Some thoughts you can consider:

Pull the spark plugs and take a look at their condition. If they are
covered in carbon/soot, then the engine is running rich. Either clean them
using sand paper and re-gap them correctly, or replace and gap w/new plugs.

Also make sure that the coolant gauge starts cold and goes to above the
middle mark when hot.

Replace the air filter if it has not been done recently, and also thoroughly
clean the throttle body using TB cleaner and an old toothbrush. Make sure
the throttle body choke plate seats cleanly all the way around.

Bob

 

Thanks for your advice. I cleaned the throttle body really well, and
that did help a little. RPM's became steady at about 1500-1600 instead
of approx 1800. coolant gauge never gets up to the middle point, so I
installed a new coolant temp sensor. The rpms initially (for about a
minute) were a little lower, 1400 or so, but are consistently even
higher now, 2000 rpms, and not so steady. the range is from about 1800
to 2100, mostly right at 2000. also, I ran the engine for awhile
bypassing the air filter with the same results, so it isn't the filter
either. Not sure where to go from here. also, do I need to reset the
onboard computer faults, or would the computer do that itself?

 

LOL...I got the same thing, Scott.
Thanks for the advise, Bob.....I had just replaced my plugs 4 weeks
ago, so I checked them & they were fouled. Cleaned & re-gapped them.
Pulled throttle body off and cleaned it really well. Replaced IAC.
Now Car starts at 3000 rpms and immediately begins to drop until it
hits 1900. I let it run 10 -12 minutes.....it climbed up to around
2500....lol.
My coolant gauge has never reached midway point either.
I disconnected battery for 30 minutes to try to reset PCM....does that
do it?
Isn't there a way to reset it? Could this problem just be the PCM
still trying to compensate for the earlier problems and needs to be
'reset'?
Thanks again guys.