I have 2002 Montero Limited that when in fifth gear and around 2000 RPMs begins to vibrate, almost like a cylinder ping, but worse. It only stops if I down shift to fourth or accelerate. I test the ignition with a timing light, and the even number cylinders are missing or not firing at all when reved up. When I took the wire off the coil pack, and started the engine there was a constant arc across the coil to the plenum they are bolted to, which leads me to believe that there is nothing wrong with the coil packs. The truck has 100000 miles on it. I change the plugs and wireset around 65,000 miles and put Bosch plus-2 plugs and a Bosch wireset on it. Any help would be appreciated. Thanks.

 

Can you specify which engine? Did you do a compression test? Have your injectors been serviced at all recently?

 

It is the 3.5. No, I have not performed a compression test and again no, I have not removed and serviced the injectors if that is what you mean. I do run Lucas Fuel Injector cleaner through it periodically. Also, I have some updated info regarding the ignition. The even number cylinders are firing fine. I think I had the timing light on wrong. Anyway, at idle it seems that the odd number cylinders are firing twice as fast as the even number cylinders. Thanks for your help.