Question about 2004 Chevrolet Impala
My 2004 impala (3800 engine) is misfiring. It was lean and I replaced the O2 sensor but it is now misfiring at 2500 rpm. It misfires regularly when I give it gas. on the open road, it begins misfiring at 35 mph. I replaced the plugs and wires also. I found a vacuum hose that was cracked and replaced it but I wonder if there are others and this could be the cause of the misfire.
Check your bank 2 plugs for colour (do they look hot like they running hot ). Check you EGR Exhaust Gas Recirculation valve (looks like a 80mm diameter spaceship with a vacuum line to the top of it) If this remains closed the engine runs very hot and causes misfire. Possible causes are EGR not opening are 1) perforated diaphragm 2) encrusted valve stem 3) clogged exhaust gas feed pipe. A quick check for function: run the engine and remove the vacuum tube. The engine note should change as the tube is connected and then disconnected. Also pushing on the underside of the EGR with your fingers to lift the diaphragm to open the valve should also result in change in engine note. If its not working just disassemble the EGR and clean with carb cleaning spray, also clean the exhaust gas feed pipe likewise.
Posted on May 04, 2010
There should be no built up fuel or oil in cylinder. The fuel will be burned off immediately, and there should have been very little unless you have a leaking injector. The only way oil will enter the cylinder is if you have a mechanical failure like worn rings or leaking valve seals.If after replacing the plugs and wires did not correct all or the skip after the first start up and road test then you have another issue causing the skip
Posted on May 23, 2010
Please read the info on this at this LINK
Posted on Jun 14, 2012
Testimonial: "Thank you. Found a leaking fuel pressure regulator leaking into the vacuum line. Replaced it, and engine runs great, idles smooth, but now it will not start when engine is cold. Can you help with this?"
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