cdn_olds_94 Posted October 11, 2014 Report Share Posted October 11, 2014 I've had my Cutlass for a month now and I'm still getting use to it's eccentricities. On start up it revs high and then drops to about 800 RPM then revs high once more. This happens for a minute or so, then it levels out around 800 RPM and drives fine. This happens on colder or wet mornings at first start up, but will start up fine any other time during the day. I've cleaned the throttle body and changed the PVC valve so I'm hopping that this helps the start up. Any ideas from the group if I'm going in the right direction with this or not. Thanks. Quote Link to comment Share on other sites More sharing options...
94 olds vert Posted October 11, 2014 Report Share Posted October 11, 2014 When starting the car cold it will idle higher then drop down. That is normal but revving up again is not. I would check the IAC. Idle air control valve its on the throttle body. Held in with 2 screws. Quote Link to comment Share on other sites More sharing options...
pitzel Posted October 11, 2014 Report Share Posted October 11, 2014 Yeah sounds like an IAC valve problem. If you've cleaned the throttle body and all the passages, then not much else you can do but replace the IAC actuator. Should be able to get one from a junkyard for almost nothing. They can wear out or teeth get chipped. Quote Link to comment Share on other sites More sharing options...
jman093 Posted October 11, 2014 Report Share Posted October 11, 2014 Check hoses and gaskets for vacuum leaks. Leaks are common and often difficult for owners to find on first gens. Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted October 12, 2014 Report Share Posted October 12, 2014 What year and what engine is this? I'm thinking it's your LIM gaskets. I had this issue before, but on a 1994 3.4 Cutlass. What you can do is look for the seam where the Lower Intake Manifold meets the block. It's in the center, where the V formation is. Spray carb cleaner there and if it surges, it's your LIM. It can also be a vacuum leak. Check all emission hoses and fittings. Some are hard plastic instead of rubber and can crack causing a leak. This happened to me as well... I fixed using a fuel line hose, car didn't know the difference. Quote Link to comment Share on other sites More sharing options...
cdn_olds_94 Posted October 13, 2014 Author Report Share Posted October 13, 2014 What year and what engine is this? I'm thinking it's your LIM gaskets. I had this issue before, but on a 1994 3.4 Cutlass. What you can do is look for the seam where the Lower Intake Manifold meets the block. It's in the center, where the V formation is. Spray carb cleaner there and if it surges, it's your LIM. It can also be a vacuum leak. Check all emission hoses and fittings. Some are hard plastic instead of rubber and can crack causing a leak. This happened to me as well... I fixed using a fuel line hose, car didn't know the difference. I have the same year of Cutlass as you with the same engine size 3.4. I'll try both your solution and the other about replacing the IAC valve, and let you know what works. Thanks. Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted October 13, 2014 Report Share Posted October 13, 2014 why replace it? if it moves it functions. it is computer controlled air metering device. just think as to why it would be commanded or not commanded to move. Quote Link to comment Share on other sites More sharing options...
94 olds vert Posted October 14, 2014 Report Share Posted October 14, 2014 Measure your IAC. I have had mine be way past the 28mm mark. If the center rod is loose you can attempt to screw it back in, if you manage to do that put the IAC back in and see if that makes a difference. Quote Link to comment Share on other sites More sharing options...
cdn_olds_94 Posted October 18, 2014 Author Report Share Posted October 18, 2014 Measure your IAC. I have had mine be way past the 28mm mark. If the center rod is loose you can attempt to screw it back in, if you manage to do that put the IAC back in and see if that makes a difference. I replaced the IAC valve this morning and the car is revving normally now. The one that was in the car was covered in carbon and had a burnt look to it. Quote Link to comment Share on other sites More sharing options...
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