Engine Mechanical problem
1988 GMC Van 6 cyl Two Wheel Drive Automatic 102, 00 miles
My 1988 GMC 1500 Vandura Van acts like it is misfiring. It was running quite badly a couple of months ago then one day it quit on the highway. I have replaced the fuel pump, relay, spark plugs and tested the wiring all the way from the fuel pump to the relay. I did have a bad ground which I fixed. Now it starts and idles fine and runs OK at low speed. But when running above 35 mph or when accelerating, it spits and sputters like a misfire and the MPG has dropped way down. I checked the injectors with engine running and there is a perfect cone of gas flowing. The 'check engine light' does not come on. Any ideas you have on what is causing it to run so rough would be greatly appreciated.
Friday, December 18th, 2009 AT 8:21 AM