I have a 1998 Toyota 4runner. I have had the same problem for almost a couple years. When I accelerate the vehicle stumbles and hesitates, it also backfires during heavy acceleration.
I have scanned the computer and the code that comes up is p0340 (cam positioning sensor). There was also code for ignition coil pack but that went away when replaced with new coil packs.
The engine us 2.7L
I have replaced cam positioning sensor, ignition packs, wires and spark plugs.
One of the spark plugs was cracked and It ran great or about 2 weeks after the spark plugs were replaced. After about two weeks it started to stumble and backfire again.
About a week ago I was checking the crank position sensor for resistance and voltage an I noticed oil inside the plug. I cleaned the oil out and plugged it back in and it ran great for about a mile or two then it started to run rough again.
I have checked the the resistance and voltage on the cam and crank positioning sensors. I have checked the timing chain and it hadn't skipped a tooth. It appeared to be fine as well.
I'm really stumped and don't know what to do now.
I had also changed the fuel filters before a code had come up.
have the same problem?
Sunday, June 12th, 2011 AT 10:51 PM