2001 sc1 Cyl 1 misfire

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.