jmoore4294 Posted January 5, 2008 Report Share Posted January 5, 2008 So, when I shift out of park to reverse, the whole car like jolts. Then when I shift from reverse to drive, the whole car jolts and well, you get the idea. My question is, is that just an engine mount gone bad? I know they've never been changed, and I have 146,000 miles on the car. Quote Link to comment Share on other sites More sharing options...
Andrew Posted January 5, 2008 Report Share Posted January 5, 2008 it there is a thud or thunk sound with it, then yeah could be mounts. id the idle high at all? if it is, then shifting will cause a jolt like that. Quote Link to comment Share on other sites More sharing options...
jmoore4294 Posted January 5, 2008 Author Report Share Posted January 5, 2008 Oh yeah, it comes with a THUNK. As for the idle, it sits at about 950....maybe 1000 RPM. And that's after it has warmed up. Quote Link to comment Share on other sites More sharing options...
1990lumina Posted January 5, 2008 Report Share Posted January 5, 2008 Probably a mount or 4 lol...mine are bad too (two lower ones) and they cause that banging sound. Quote Link to comment Share on other sites More sharing options...
rockfangd Posted January 7, 2008 Report Share Posted January 7, 2008 that idle should be a bit lower though when shifting int gear. You may want to check you CPS and see if it may be innacurate Quote Link to comment Share on other sites More sharing options...
Andrew Posted January 7, 2008 Report Share Posted January 7, 2008 that idle should be a bit lower though when shifting int gear. You may want to check you CPS and see if it may be innacurate thats about where my old 3.4 would idle Quote Link to comment Share on other sites More sharing options...
Schurkey Posted January 7, 2008 Report Share Posted January 7, 2008 Oh yeah, it comes with a THUNK. As for the idle, it sits at about 950....maybe 1000 RPM. And that's after it has warmed up. Both of mine idle around 650. So I'd say a too-fast idle speed is your cause. The underlying issue is why is the idle speed so high. Defective Idle Air Control??? Quote Link to comment Share on other sites More sharing options...
Psych0matt Posted January 7, 2008 Report Share Posted January 7, 2008 I idle around 750-800 Quote Link to comment Share on other sites More sharing options...
rockfangd Posted January 8, 2008 Report Share Posted January 8, 2008 Oh yeah, it comes with a THUNK. As for the idle, it sits at about 950....maybe 1000 RPM. And that's after it has warmed up. Both of mine idle around 650. So I'd say a too-fast idle speed is your cause. The underlying issue is why is the idle speed so high. Defective Idle Air Control??? That is also possible. I would not shift my car into a gear at anything higher than 850 Quote Link to comment Share on other sites More sharing options...
jmoore4294 Posted January 8, 2008 Author Report Share Posted January 8, 2008 Any suggestions on what to pour all my money into first? Quote Link to comment Share on other sites More sharing options...
jmoore4294 Posted January 8, 2008 Author Report Share Posted January 8, 2008 Alright, so I went and got some TB Cleaner and took the IAC off and gave it a good spraying and cleaned it (man was it covered in gunk) And so far, no change. The idle still sits at 1000. Maybe, if I replace it? Or do you figure it would be something else. Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted January 8, 2008 Report Share Posted January 8, 2008 When you say it idles at 1000, to you mean in park, or do you mean in gear? If in park, that sounds about right if maybe a tad high. I'd put my money on the dogbone or other motor mounts. Pop the hood, and watch the engine when someone holds the brake and puts the car into gear. If it moves or jumps substantially, then you probably have a bad mount. Quote Link to comment Share on other sites More sharing options...
jmoore4294 Posted January 8, 2008 Author Report Share Posted January 8, 2008 It's 1000 in park, then drops to somewhere in the neighborhood of 900 when in gear. But I'll get my sister to sit in the car and put it in gear WITH the brakes on (knowing her though, she'll just run my ass over ) Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted January 8, 2008 Report Share Posted January 8, 2008 It's 1000 in park, then drops to somewhere in the neighborhood of 900 when in gear. But I'll get my sister to sit in the car and put it in gear WITH the brakes on (knowing her though, she'll just run my ass over ) Well 900 in gear does sound a tad high, but considering the accuracy of the tachs in these cars, it is probably just fine. As for safety, you should be able to see the movement just fine from the side of the car Quote Link to comment Share on other sites More sharing options...
jmoore4294 Posted January 8, 2008 Author Report Share Posted January 8, 2008 OK, I know the questions are getting irritating...but this is the last one. I noticed the IAC had a spring on it, should it spring back when I push that little piston in? Or should it just kinda go in and stay there and not bounce back? Should I just go ahead and replace it? Auto Zone has em for $46. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted January 8, 2008 Report Share Posted January 8, 2008 You shouldnt mess with that needle valve. Thats what controls the air going in the intake when your idling... hence Idle Air Control valve. It moves in or out to adjust to make up for air to gain more or less air in the intake. Honestly it sounds like your trying to find something wrong. Sounds normal to me to have the car move like that when the tranny is shifted into a different gear. Its all in the pressure of the tranny fluid. The engine may be warm but the tranny fluid might not be. Not all fluid warms up at the same rate. Dont mess with your car anymore. Your spending/wasting money on shit that isnt wrong. Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted January 9, 2008 Report Share Posted January 9, 2008 I agree about the IAC... what you describe is normal behavior, and it doesn't need to be replaced unless there you observe symptoms of its failure (and you havent mentioned any). The idle numbers that you have posted, while they are a little higher than some have quoted, are not out of the normal range seen on GM 60* V6 engines, so I wouldn't be at all concerned about it As for the jolt you describe, some jolt is normal (but I imagine you know that), as you load the drivetrain and mounts by putting the car into gear. However, if that jolt seems harsh or excessive, your motor/tranny mounts could be going south, allowing the engine to move more substantially upon going into gear. Considering you mention that your mounts have high miles on them, it is very likely that at least one is not performing as it once did. Whether or not any of them have completely failed, you would likely notice an improvement by replacing them, and so I'd probably recommend that you change them as an act of good maintenance. Quote Link to comment Share on other sites More sharing options...
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