I have a 2012 Chevy Equinox LT 2.4L it is misfiring badly. Coded it and codes P0302 came up, but also code P0300 this code came up twice and then it was just the 302 code. We changed all 4 spark plugs, changed the ignition coil to cylinder 2 and also changed the Purge valve solenoid ( car was running fine, got gas and 4-5 miles down the road it started sputtering, jerking back, no power going uphill, running really rough) we also put HEET in it thinking possible water in gas due to possibly bad gas! Nothing changed. RPMs are at 1000 and then bog down or will either stall! I am at a loss now, any help greatly appreciated. (still codes to a P0302 after repairs)
Check the fuel pressure. An idling engine doesn’t take much fuel to a faulty fuel pump or regulator may do just fine under those conditions. That all changes once you put more of a load on it.
Go back to the gas station and ask if there’s been other complaints like this immediately after buying gasoline there. Perhaps they are aware of a problem. HEET is a good product but can’t work miracles. For example I doubt it would help if the gasoline was contaminated w/ diesel fuel. If nothing obvious turns up on further diagnosis what I’d probably do it have the gas tank drained and re-fill with fresh gasoline and see if that helps.
Are you sure it was gas and not diesel you put in? It happens all the time.
yes, it was gas for sure!
People keep telling me to add Seafoam to my car. To put it in the oil, gas tank and brake booster line? Is this safe and also helpful?
I would switch the coils of Cyl 2 with a coil from another cylinder to make sure you have a good coil. If the problem moves to the other cylinder you have a bad coil (even if new).
Check the fuel pressure and check for vacuum leaks. At least once you had a random misfire (P0300) and they usually do not correct themselves. Don’t waste your money on SeaFoam. It won’t work in this instance.
ran diagnostic on it. Only cylinder misfiring is 2, all the other cylinders were fine. Fuel pressure was good. We changed the coil in cylinder 2 and switched them around. We also unhooked each coil all of them but Cylinder 2 bogged down. There was no change. Thought coil was bad, got a new one and still the same thing, everyone but 2 bogged down when disconnected ( going to run a test on it to see if coil 2 is getting power to it).
We did a computer diagnostic on it! It wasn’t at a shop, but my friend brought his computer diagnostic over. So we are thinking it is either injector (fuel balance test on the injectors were 48 for Cylinder injectors 1 and 2,Cylinder injector 3 was 0.07 and Cylinder 4 was 204), or cylinder itself! Draining tank tomorrow and putting in good gas!
Well just going to have to chalk it up and take it to the shop…ugh!!! tried everything we could…lol! Some things needed for testing we do not have. Tested the power to all the coils…fine. Got the fuel rail out ( that was so much fun…lol) and check the resistance on all the injectors… evidently I have low resistance injectors because they all were stable around 3.6 when tested with the millimeter. Cleaned all the injectors. Could of replaced number 2 injector since it is misfiring on cylinder 2, but decided to take it to a mechanic. Don’t want to waste the money if that is not the problem! So we will just see what the mechanic comes up with!