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Showing results for tags 'random misfire'.
Found 4 results
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Hello I have a 2000 GMC Sierra 5.3 4x4, it has been sitting for 6 months. First thing I did was change the oil, next I drained the old gas and put new gas in. The truck would crank but not turn over. I replaced the fuel filter, and replaced the fuel regulator. Prior to replacing the fuel regulator I had no fuel pressure, gas was leaking through the diaphragm of the regulator into the intake manifold. Once I replaced the above items fuel pressure was up to 50psi with key in start position. The truck fired right up no problem but, there was a very loud ticking sound that sped up and got louder when I pushed on the gas. I immediately shut it off. I checked the oil and the dipstick smelled like gas. I drained the oil and there was a lot of gas mixed in with the new oil. I replaced the oil filter and filled it with new 5W-30 Mobile 1 high mileage synthetic oil. It fired right up again and the loud ticking sound was still there. Oil pressure was good I let it idle for a few minutes and the ticking got a little bit quieter but, still loud. Check engine light was on and the codes were P0300 and P0200. I hooked up a Noid light to each injectors wiring harness at idle and every one was firing. I removed the fuel injectors and cleaned them, did OHM test on each one and all of them had consistent readings. I do not know what else to do from here? Any help, direction, or advice would be greatly appreciated. Thank you for taking the time to read this. My truck has 245,000 miles on the original engine.
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Hello I have a 2000 GMC Sierra 5.3 4x4, it has been sitting for 6 months. First thing I did was change the oil, next I drained the old gas and put new gas in. The truck would crank but not turn over. I replaced the fuel filter, and replaced the fuel regulator. Prior to replacing the fuel regulator I had no fuel pressure, gas was leaking through the diaphragm of the regulator into the intake manifold. Once I replaced the above items fuel pressure was up to 50psi with key in start position. The truck fired right up no problem but, there was a very loud ticking sound that sped up and got louder when I pushed on the gas. I immediately shut it off. I checked the oil and the dipstick smelled like gas. I drained the oil and there was a lot of gas mixed in with the new oil. I replaced the oil filter and filled it with new 5W-30 Mobile 1 high mileage synthetic oil. It fired right up again and the loud ticking sound was still there. Oil pressure was good I let it idle for a few minutes and the ticking got a little bit quieter but, still loud. Check engine light was on and the codes were P0300 and P0200. I hooked up a Noid light to each injectors wiring harness at idle and every one was firing. I removed the fuel injectors and cleaned them, did OHM test on each one and all of them had consistent readings. I do not know what else to do from here? Any help, direction, or advice would be greatly appreciated. Thank you for taking the time to read this. My truck has 245,000 miles on the original engine.
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Re-posted from wrong sub forum, hope this is the right one. Hello everyone. I operate a business and have several work trucks, most being 1-ton's with flat beds, with welding machines on the back. The last work truck I purchased was a brand new 2015 GMC 3500 with no bed. I installed the flat bed and put all my welding equipment on it here at my shop. The truck worked flawlessly for the first year or so. I run a welding fabrication company and my rig trucks are pulled into shop and locked up each and everyday. Some days the trucks will be cranked up for 1-2 minutes and pulled out into the front of shop. In the afternoons they will be pulled back in and locked up. This could happen for several days in a row or maybe a week. Sometimes they will be run everyday on local jobs and run 20 miles or less. I take care of all of my equipment and do regular oil changes when necessary. The particular vehicle in topic is a 2015 GMC 3500 HD with 6.0L gas burner (8'700 miles). It has passed 3 year warranty. It has had selected "bad" spark plugs replaced maybe 12 spark plugs in total. The truck would start running bad while driving and start to have a hiccup and bad idle/misfire. I would take it to the dealership and they would diagnose it with a random misfire in cylinder "x" and they changed the plug in question. The cylinder(s) were mostly different each trip in. I would receive the truck back, codes cleared, and the truck would continue to run like a top for several months before issues arose again. I would take it back and they would change the spark plug(s) and problems gone. I don't have the code on hand at the moment but I remember hooking it up to a snap on diagnostic tool and the code was random misfire. I vaguely remember the code being p0300. I have since bought OEM spark plugs myself once. I hooked up diagnostic tool and it showed cylinder #7 had a misfire. I replaced #7, cleared code and issues went away for months. The problem just came back again this week and I am near sick of changing spark plugs on a vehicle with 8700 miles on it. What should I do, what could be causing this issue? Let me know if any more details would help. Thanks, Bear. -
HI Everyone I have a 1999 GM 1-ton with a rebuilt 350 in it. We put on new distributor, cap, coil, plugs and wires. The truck starts and runs good. but when under certain driving conditions (full throttle, or certain revs) the truck will backfire, hesitate etc. When a timing light is used the truck is timed right, but every so often it will throw a spark when the crank is 90 degrees past the timing marks. It is random when it happens, but it always happens in exactly the same spot. So it will fire 3 or 4 times on the mark and than once 90 degrees past and than back to the marks. My question is what could be causing this? I think 90 degrees on the crank is 45 degrees in the distributor, but how could the rotor be lined up to the next spark plug but jump back to #1? Any guidance or insight would be greatly appreciated, Thanks in advance.
