Question94 4runner 3.0 v6, manual trans, 200k miles has had an intermittent bucking problem at light to moderate loads for more than a year. Initially, it would run fine 90% of the time, having problems when the humidity was high. Recently it runs like crap all the time. For the past few years the engine light would come on at random and then go out. Now there is no engine light, and no code indicated in diagnostic mode.
Have taken this to 3 different mechanics including the local Toyota dealer. In the past six months have replaced; throttle position sensor, fuel filter, fuel pump, distributor cap, rotor, air filter, coil, plugs and most recently the Toyota
shop said MAF sensor is bad (replaced today). EGR valve seems to function normally based on the fact that it opens when vacuum is applied @ 2000 rpm and closes when vacuum is removed. Have checked for vacuum leaks, leaky ignition wires, and have checked the adjustment of TPS 3 times. Still runs like crap.
Eventually, I will run out of parts to replace but would much prefer to find some means of narrowing this down.
Answersounds like they threw alot of parts at it. I hope if it didnt fix it you got some type of refund.
Define- "runs like crap".
runs poor when hot, cold, hard start, stalls, chugs on accell ?
Does it use coolant or burn oil?
Start simple.
do a compression test on it. maybe you have a dead cylinder.
Mike
