I had this problem recently, I got a new air filter, and replaced my spark plugs which fixed it. It could also be a vacuum leak somewhere, look it up on how to find it =)
tested the map sensor. test a lot of things actually. finally bought a compression test, cylinder 3 read funny, and would sometimes trigger SES light. i took it to get a second opinion and was told compression held 150 straight across, injectors were good, but differential test showed 15% off. "bent or burnt exhaust valve" is what i was told. couldnt tell me how long it would last and that was jan 3
Interesting. I'd check out the MAP sensor. With a scan tool it should show 30 at idle. If not working properly, it would not open the throttle bypass correctly, not being able to sense manifold pressure. Could also be something else not telling the ECU to set the timing correctly, though the tach is working, so it is getting the crankshaft signal. When my TPS was failing, sometimes the idle would climb high, but it'd stay there until I turned the car off and back on.
Try cleaning the air intake. Remove the air filter housing (goes from air filter to back of engine), then take a look at the valve there. If its black and gunky, clean it off with some carb spray or something, and it should straighten out.
Have an 01 SL, had the same problem and an idle sensor did the job
FastAssSaturn 1 month ago
I had this problem recently, I got a new air filter, and replaced my spark plugs which fixed it. It could also be a vacuum leak somewhere, look it up on how to find it =)
SuperJKE123 1 month ago
might be your oxygen sensor
deathkeeper5000 1 month ago
tested the map sensor. test a lot of things actually. finally bought a compression test, cylinder 3 read funny, and would sometimes trigger SES light. i took it to get a second opinion and was told compression held 150 straight across, injectors were good, but differential test showed 15% off. "bent or burnt exhaust valve" is what i was told. couldnt tell me how long it would last and that was jan 3
jdilla007 10 months ago
Interesting. I'd check out the MAP sensor. With a scan tool it should show 30 at idle. If not working properly, it would not open the throttle bypass correctly, not being able to sense manifold pressure. Could also be something else not telling the ECU to set the timing correctly, though the tach is working, so it is getting the crankshaft signal. When my TPS was failing, sometimes the idle would climb high, but it'd stay there until I turned the car off and back on.
td1238 10 months ago
Try cleaning the air intake. Remove the air filter housing (goes from air filter to back of engine), then take a look at the valve there. If its black and gunky, clean it off with some carb spray or something, and it should straighten out.
Happened to me on my 2000 ls around 150k.
marcusmw1 11 months ago
i got the exact same problem with the exact same car....1999 sl2 automatic (green) with about 140k
ButterOnMyBiscuit 1 year ago