I HAVE A 1998 GMC JIMMY THAT RUNS ROUGH WHEN IT IS COLD, AFTER IT WARMS UP IT RUNS GREAT.
I HAVE CHANGED PLUGS, WIRES, DIST CAP, EGR, O2. CAT CONVERTER, MUFFLER, MAP SENSOR, THROT POSITON & AIR FILTER.
I DON'T KNOW WHAT TO DO NEXT, PLEASE HELP.
It is normal for a car to run " rough" when its cold. Let your car or truck warm up a bit before taking off. Notice the RPM's. When they get towards the 1 or below, and your engine temp guage reaches midway you know its safe to take off and your car is warmed up.
November, 29, 2006 AT 9:46 PM
ANY CHECK ENGINE LIGHTS ON, THEY DO HAVE A PROBLEM WITH THE INJECTOR POPPET VALVE STICKING WHEN VEH. IS COLD COUSING A MISFIRE, GM CAME OUT WITH NEW INJECTORS FOR THAT PROBLEM. ALSO HAVE U CHECKED UR FUEL PRESSURE, MAKE SURE IT HOLDS, UR FUEL PRESSURE REGULATOR COULD BE LEAKING COUSING VEH. TO RUN ROUGH BECAUSE OF THE RAW FUEL IT DUMP OVER NIGHT. DO U HAVE A HARD START WHEN VEH. SIT FOR A LONG TIME IF SO U HAVE A FUEL PRESSURE REGULATOR THAT LEAKS.