low rough idle

[lewis1952]

I have a 2000 SE 3.1 and it idles at about 800 and rough. Pontiac said it should idle about 1200 -1500 at operating temp. I have changed plugs,wires,TPS, IAC, cleaned throttle body and MAF. What else am I missing.

[Below Average Joe]

vac leak

[lewis1952]

Thanks Joe I'll check that

[Scottydoggs]

no way it should idle at 1200 or higher warmed up, it should be at 800 in park warmed up.

1200 on a cold start up for a short time then the idle should drop to 800.

take a can a carb cleaner and spray the vac lines while the car is idling, if the idle jumps up you found the vac leak area.

also make sure your plug wires are on right. if this all started after the tune up.

[lewis1952]

Thanks Scotty. Yea I went out to the car and using the pedal took it to 1200 and what the hell.

[lewis1952]

Scotty went out to ck for vacuum leaks like you said. Started the car it runs as smooth as a new one. Idle at 1100. As it warmed up it slowly went down to 900 still running great. Last nite it ran so ruff I thought it would stall any minute and I didn't do anything to it. But there is a strong smell of varnish you know like a gas tank that hasn't been used in a long time. You ever encounter this ?

[dsmuts]

No check engine light?

[lewis1952]

no DS no light scanned it no codes .The other day I scanned it had these codes: 135,341,300 and 405 idled like crap today smooth as silk and no codes. I have no idea whats going on with this thing.

[tech3627]

A very common vacuum leak on the 3.1 is were the vacuum lines connect to the top of the plenum just behind the throttle body. There is a rubber boot that falls apart. It can be replaced with a small piece of 3/8 fuel line. I have seen these leak intermittently. Check that connection close. The codes you have are for an O2 sensor heater, cam sensor, misfire, and EGR position. The EGR valve can stick intermittently and cause it to run rough. It normally sticks due to carbon buildup. Try removing the EGR valve and looking at the pintle. It is best to do this when it is acting up.

[lewis1952]

thanks Tech I know the fitting you are talking about 'll ck it

[dsmuts]

Swap your cam sensor. That'll make it run like poop