I have a 2002 GMC Savana 5.7L that has multiple misfire codes on the scanner. I have replaced the map sensor, mass airflow sensor, plugs and wires, cap and rotor, and had the fuel and exhaust systems checked and everything is fine there, and it also has good compression. Despite all these replacements and checks, it still shows the codes, it has no power under load or going up hills, the check engine light flashes when going over 60mph. It also hesitates and will not shift at that speed until I let off the gas. Does anyone know what is wrong/how to fix this? Thanks for any help!
The flashing check engine light indicates a misfire. Did you check the crank sensor? Is the fuel pressure within the manufacturer's specs?
January, 1, 2013 AT 2:21 AM
Yes, the crank sensor is fine and so is the fuel pressure. I had the dealership run a diagnostic test on it today, just to find out the same results my mechanic found-no fix and a waste of money and time. Has anybody tried a Dyno machine to locate the source of the problem?