rough idle

[spydog]

hi guys i have a 1999 SLE and at idle my rpms go up and down a bit maby between 700 rpm to 1000rpms anny sugestion on what i can look for or what may be my problem?

[charliemax]

Have you been working around the engine any? One possibility is you have a small vacuum leak.

[spydog]

i replaced the upper intake this last summer about 4K ago

[spydog]

i pulled the car in the garage nast light and i noticed sone green coolent on the lower intake manifold i am thinking i didnt get the upper plastick intake tight enough when i replaced it this last summer what do you guys think i couldnt get to all the bolts because of the fule rail but the ones i could get to i could almost turn 1 full turn

[bill buttermore]

... i couldnt get to all the bolts because of the fule rail but the ones i could get to i could almost turn 1 full turn

That would be a problem. Loose bolts could allow a vacuum leak causing or contributing to the erratic idle, and on the throttle body end, if the UIM bolts are not uniformly tightened, you could see a coolant leak as a result. It is not that difficult to lift the fuel rail to gain access to the bolts. Read through this Techinfo procedure to see how. You might also want to consider changing out the LIM gaskets and getting rid of DEX if you have not already done so. Read this Techinfo article to understand why.

Some other causes of erratic idle include: idle air control valve, dirty throttle body, and faulty throttle position sensor. But the most common and likely cause is a vacuum leak.

[spydog]

ok thaks for tjhe sugestions i will pull the car in the shop some time with in the next week and pull the fule rail and tighten the upper intake bolts do u have a torque spec on th bolts?

[bill buttermore]

ok thaks for tjhe sugestions i will pull the car in the shop some time with in the next week and pull the fule rail and tighten the upper intake bolts do u have a torque spec on th bolts?

look in the articles linked for you above.

[spydog]

i removed my fule rail this last weekend and tightened up the upper intale and the rough idle went away allmost all the way i may have to replace the gasket this summer agen

[bill buttermore]

Glad to hear it. Thanks for letting us know.