1999 Chevy Monte carlo 3400 V6 SES light problem. Finally got a OBD 11 tester and i have a P0300 and P0302, or a misfire in #2 cylinder. Rechecked plug and wire, replaced wire, replaced coil for that cylinder. Sounds a bit better but still idles like a misfire, tester shows a misfire that is the only bad cylinder whats next, resistance on the injector, or would that have shown up on the tester?
Answer: Thank you for the tip / donation. Assuming there is no engine mechanical problem with that cylinder- like a rocker arm stud has pulled out of the cylinder head, most probable cause is the injector. Scanners dont detect specific problem (injector bad) just the type of fault. Our injectors today dont usually fail because of low resistance anymore. They almost always fail because they are plugged.
Here is a little trick, with the engine at idle, and missing, take a socket extension and tap the injector. Very lightly at first a few times, then a LITTLE harder if it has not cleared up. Be careful not to tap too hard and crack / punch hole in the injector. This procedure will almost always free-up a stuck injector. If it does, it may quit again in a day or two, or may last a month- hard to say. If the injector does free-up, would suggest an injector cleaning service and fuel filter after replacing the bad injector.
4-5-11 I recently purchased a 2005 Chevy Impala here it is only 10 days later and it's idling so high that I don't even have to put my foot on the gas it just takes off all by itself but you have to keep your foot only on the brake at all times. Please help?!
8-9-11 my 2007 Chevy Impala doesn't want to take off fast it takes time an then it shakes an the rpm moves it self
Could be a lot of things. Engine misfire, low fuel pressure, MAF sensor, ECT. Get a scan of the computer codes even if the check engine light is not on.
1-20-12 I just replaced my spark plugs in my 2009 Chevy Impala with the 3.5 l engine. My service traction control light came and its running very rough. Could this be a faulty plug or incorrect gapping? I installed the Pulstar pulse plugs.
2-2-12 i had a random multiple misfire on a Chevy Tahoe i changed the spark plugs,wires,dis cap rotor button,and 6 of 8 injectors the car ran fine after the work but the next day it started right back with the same thing.
If after changing all that, and basically guessing, the truck is not fixed. That is why we always stress doing proper diagnosis. If that were done, you would have saved a lot of time and money. The problem depends on what cylinders were misfiring. If they were all the Odd numbers, then this may be a common problem of the left catalytic converter being plugged. If it only happens when cold, that could be an intake manifold gasket leaking vacuum. You could also have a contaminated gas. A sample would need to be taken.
Problem with my 1997 Chevy Monte Carlo LS. 3.1L V6 engine Check engine lights flashing and OBDII codes p0300. Change all sparks plugs and wires. Why does my check engine light have this code p0300. We replaced coils and spark plug wire.
Answer: First you need to find out which cylinder(s) is misfiring. If plugs and wires were replaced, another common cause for misfiring is a burned / corroded ignition coil. That should have been obvious while replacing the plug wires.
Problem with my 1995 Monte Carlo Z34. 3.4 DOHC. Work done to repair this problem = Replaced Idle Air Control Valve. My 3.4 idles VERY rough and dies cold. When warm the idle is somewhat erratic and although a little high it is tolerable. I cannot find any vacuum leak which is what I suspect. I replaced the idle air control valve and am now suspecting the EGR (it is digital). I'm not sure if it can be cleaned or not...... Any suggestions?
Answer: This IS a classic sign of a vacuum leak on the Dual Overhead Cam Motor (DOHC). Especially the lower intake manifold gaskets as they meet the head, the PCV valve pipe on the drivers side rear of the rear cylinder head, or the brake booster vacuum hose. Concentrate spraying carb cleaner on these areas when warmed up to see if the idle will change. Be sure to stay away from any ignition source, as the spray is VERY flammable.
Try tightening down the upper intake a little more and see if that helps. I had that same code come up on a 3400 and it was the upper intake.
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