help please I have took to 3 garages none can fix. First have 94 camaro z28 have brand new engine and transmission (don't ask what that cost) ) LT1 The idle goes crazy on it some times it idles at 3k rpm and when driving down the highway i go 70 with foot off the gas. Have replaced the mass air flow and throttle body sensor. no help and after it idles for a little bit the check engine like comes on they said it says egr thing i replace that also another 100 no help. The idle slows to 800 rpm when the check engine like comes on. IM going broke buying parts think it main computer ? thanks for any help

 

Have you scanned it for codes? Has any of the three garages scanned it for codes? If so, what were the exact numerical codes?

Have you checked the throttle linkage for binding? Are you sure the throttle blades fully close under all operating conditions?

Engine can't idle high, or run you to 70MPH with your foot off the throttle unless its getting a lot of air. Either the throttle blades are not closing, or there is a huge/variable vacuum leak.

But if you have an SES light, you have to pull the code(s).

 

Its not the out side linkage i oiled that and it goes back every time but that makes since the inner flap must be opening to make it run fast think it is sticking or the computer is making it open ?? thanks so much for help

 

they said only thing it shows is egr value

 

The computer can't control the throttle opening unless you have the cruise control engaged.

Verify the blades are closed by looking at them, not at the linkage. There is a throttle stop screw on the throttle body - is that adjusted correctly?

There are two codes in OBD-I for EGR. Which one did you get? You really need to have it scanned and get the exact codes.