Vibration and Thumping - Nissan Pathfinder

Our 1999.5 Nissan Pathinder has about 148,000 miles on it. At the end of 2011, we replaced the struts, shocks, and brake pads. We also added a new in-dash stereo with GPS. At the end of 2011, the mechanic recommended replacing the ignition wires, cap/rotor, and spark plugs, all of which were OEM. The mechanic also recommended replacing the power steering belts and serpentine belts, which were cracking. We did not do these repairs in 2011.

At the beginning of February 2012, I drove the car for several miles and then parked for 30 minutes. When I re-started the car, the engine made a thumping sound and the whole car vibrated. The thumping sound was a dull sound (not a pinging). These symptoms occurred in Park. I drove about 100 feet down the parking lot (using both Reverse and Drive) and the thumping sound and vibration continued. I parked and re-started the car. The symptoms continued for about 1/2 mile driving and then went away.

The problem has occurred 2-3 times more. To my knowledge, the problem has only happened when the car has been driven, left standing for 15-60 minutes, and then restarted. Each time the problem goes away shortly after it begins. The third time the problem happened, the “Service Engine Soon” light went on. We took the car to a different garage. The computer showed two codes (Cylinder 2 Misfire, which had been tripped 3 times), and Engine Vibration.

The mechanic recommended doing the service that we had put off in 2011 (ignition wires, cap/rotor, spark plugs, power steering belts, and serpentine belts). The theory was that a mis-firing cylinder may have caused the engine vibration. So, we had this service done. The next morning after picking up the car, and again after a short drive, a 30-minute delay, and restarting the engine, the problem happened again. So, it seems that the service did not fix it. Any ideas?

Have a good mechanic check the vibration damper on the engine. If it’s loose it could cause the vibration to occur. These are also known as harmonic balancers.

Update – The mechanic says that the fuel injector on cylinder 1 is not getting any ohms when the car turns on, so it isn’t firing, causing the engine to vibrate. The fuel injector gets power once the engine is running for a bit and then starts functioning. Does that make sense to you folks?


Yes, it does.

Your wording is a bit shaky, as an injector does not “get ohms”, an ohm is simply the measurement of its resistance though the winding, but the idea sounds basically correct.He’s saying that the injector is not firing when the engine is first started up until it gets warmed up and/or vibrated a bit. Vibration is tha standard way to free stuck components.