ABO421 Posted April 11, 2007 Report Share Posted April 11, 2007 Hope someone can shead some light for me. 94 ETC 75K, Problem started with the Tach jumping when I came to a stop at a light. Tach was jumping form 500 to about 800 RPMs and car was pushing forward. I changed plugs and Wires (AC Delco direct from dealer). Did not solve the problem, so I cleaned out the EGR valve to make sure it was not sticking. When i put the EGR valve back the car stopped pushing forward at stops, but now it is running Very rough. I can hear a deep rumble in the exaust that was not present prior. The entire car shimmies when I step down hard on the gas, and my MPGs have been slow getting worse. I Cleaned TB, but no change, I also took off EGR and made sure it was on properly and all connectors were on and secure. So now I turn to you guys for help! Any suggestion would be great. Thanks All! Link to comment Share on other sites More sharing options...
BodybyFisher Posted April 11, 2007 Report Share Posted April 11, 2007 Check this thread out: http://caddyinfo.ipbhost.com/index.php?sho...amp;hl=phenolic Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
jackc Posted April 11, 2007 Report Share Posted April 11, 2007 A bad coil could be the cause of the roughness. If yours are original, failures can be expected. The power balance test that is built into your OBD can be used to isolate dead cylinders. An idle speed control motor that is going bad could cause the idle fluctuations. Failures are common in cars this age. Sounds like it got worse after you messed with the EGR. Did you maybe create a vacuum leak? Did you replace the gasket? Do you know if the pintle was sealing in the valve after you cleaned it? And do you have a factory service manual for you car? If not, its time to get one. Link to comment Share on other sites More sharing options...
ABO421 Posted April 11, 2007 Author Report Share Posted April 11, 2007 Hey thanks for the suggestions guys I think I will start with cleaning out the Carbon and rodding out the mouse holes this weekend. I will keep you all posted on my results. Link to comment Share on other sites More sharing options...
kcd1184 Posted April 11, 2007 Report Share Posted April 11, 2007 I have done both the idle speed control and phenolic spacers on my 94 Eldo. I had the same rpm surge you have and cleaning the isc solved the problem. Guru said 100,000 for phenolic spacers. Kent Link to comment Share on other sites More sharing options...
PAUL T Posted April 12, 2007 Report Share Posted April 12, 2007 Were there any codes? Check the vacuum lines from the throttle body to the firewall for leaks. I think they are the evap lines. Link to comment Share on other sites More sharing options...
blunted Posted April 12, 2007 Report Share Posted April 12, 2007 A bad coil could be the cause of the roughness. If yours are original, failures can be expected. Definitely check the coils, I went thru this a three times with my 94 Eldo and 2 of those times it was a burnt coil and the other was a bad plug. A bad coil does exactly what you describe, bad idle, surging at idle, lunging at stops, loss of power. Link to comment Share on other sites More sharing options...
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