On one of my 95 Riviera's Supercharge the problem I am experiencing....after the vehicle sit running for an example in traffic/light/stop sign etc. the engine begin to idle rough. If I place the trans in neutral the engine smooth's out. I noticed the RPMs are near 700-800. I am of the opinion that if I could do some type of adjustment to raise the RPMS to 1000 the problem would go away. Can the idle be adjusted on these vehicles? Thanks>>>>
I have been unable to adjust the RPM's but I have minimize the "Rough Idling" problem by changing the Idle Air Control Valve. Presently I am checking that group of wiring that's leads from the ignition coils to the computer to determine if there are some broken wires exposed to excessive heat causing a breakdown in current flow. I will continue to post updates.
To Riveraman, in response to your question/concern. Is it when you first start the vehicle that its experiencing the high RPMs, if so turn the vehicle off and restart it. If the RPMs then returns to normal then I suggest that you check the TPS Sensor. This can be done at any auto parts shops.
Great news/update. The Riviera is now performing as well as if it was new. If you recalled this vehicle would lope/jump, run rough when idling and the service engine light stayed on. We discovered a couple of issues. One of the major and most compelling was that during the changing of ECMs apparently the wrong chip was installed and secondly we found that the throttle body has a small crack. Thanks to all that provided information. During research I discovered information that provides the type/model/part number of an ECM and the appropriate chip related to each ECM. In addition the parts' personnel at your local GM dealer can be a great resource in paring the correct ECM to the correct chip. Maybe even better than the info. posted on the internet. But the internet is a great place to start your research. Got a problem, hang in there and don't give up.
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