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99Sunfire 2.4L Automatic ~ Sounds like a Diesel


rayzur9
10-05-2006, 01:31 PM
Just reached the 120K mark on my Sunfire. The avg. Temp here in TX is 80+F in the morning, and humid. Nice huh? I noticed when I start the car, I mean when I just start the car, like within 3 seconds of turning the ignition key, that when the engine fires up the idle is high for just 2 seconds and then tapers back down to normal idle with no noise. It is during that first 2 seconds at high idle that something sounds like a diesel engine for a second and a half and it goes away, then the idle tapers down to normal and the sound is gone. Sounds like a tractor starting up, but it idles nicely. Ive always kept up with the usual maintenance, Air filters, oil changes, just did spark plugs (AC Delco platinums only!) and have replaced the vacuum tube to the MAP sensor, because it was cracked all to hell. I pulled the air cleaner assy off the top of the throttle body and cleaned it all out with TB cleaner and replaced the air filter again. Seems like when I use super unleaded, and add fuel injector cleaner, it doesnt make that sound when I start it. But after a week or two the noise will start to come back. Now, this noise only occurs upon starting the car and goes away within 4 seconds of starting.
Anything I should look at? Ive never taken off the IAC valve and cleaned it or anything like that yet.
Any ideas you guys can offer would be greatly appreciated.

Blue Bowtie
10-07-2006, 09:58 AM
Your description may indicate lack of lubrication on cold start. What oil is in the sump? Perhaps just as important, what filter is installed? Some filters do not have an anti-drainback valve, aggrevating the dry start condition.

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