| Peripheral Question - 455 Woes [message #298429] |
Thu, 31 March 2016 20:46  |
Paul Kirsch
Messages: 21
Registered: September 2015
Location: Tucson
Karma:
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Junior Member |
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Hello everyone! I have a question peripheral to our GMC motorhome experience, but perhaps some of you will have ideas.
In addition to my 1976 Glenbrook with 455 engine, I also own a 1976 LeSabre with a 455 engine. Since I have owned it, it has missed at idle and mid-throttle, but seems smooth at full throttle (both in neutral and under load). I have replaced all the vacuum lines, thermal switches and EGR valve, and checked for vacuum leaks by plugging/pinching lines; replaced the entire HEI distributer and verified a steady voltage into the distributor; installed a rebuilt Quadrajet and fuel pump and blew air through the feed and return lines to the tank (and tried running with the cap removed). After measuring uneven (107-127 PSI) compression, I took the car to a local shop for an opinion; they recommended the heads be rebuilt. I got the car back today and...it still misses at idle and part throttle.
Anyone experience something similar with their Olds 455?
Tucson, AZ
1976 Glenbrook with MAC dash, Alcoa wheels, Patterson carb, headers and A&E awning.
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