dahkodah

looking for help before I go to a mechanic and start that process...98 4runner approx 170K miles...was running fine, literally all of a sudden at a red light the engine started running rough as if it was going to stall...it starts fine every time, mildly rough during idle in park but stutters when you give it gas until the RPMs come up...if you put it in gear it really gets rough and seems to be struggling but will drive and not stall...no warning lights until today the check engine came on...any suggestions or similar experiences...I want to resolve on my own if I can to reduce the cost...sorry for long thread and for any/all help....have since pulled MAF and cleaned...looked clean...and have replaced the pre cat O2 sensor and pulled the EFI and disconnected the battery and still runs the same with CEL still on...should I change the post cat O2...have not diagnosed so no codes...is continuing down this path a waste of money

04 Rocko Taco

Take it to Auto Zone and have them read the code for the CEL, and see what that tells you, post up and let us know what it was, and lets go from there.

dahkodah

thanks will do that tomorrow morn

04 Rocko Taco

Cool deal!!

GVOLCRunner

ok, so this may also be related to TPS.. throttle position sensor.. another cranky toyota sensor that has a way of dieing and being a big pain in the butt. QUestion, when ou hold the brake; does it idle more rough then in P or neautral with ebrake?

If so, it sounds like your TPS.. which may just be out of adjustment... ts been while since ive tinkered with mine..

Since you said at a red light, which im thinking means your brakes were on.. it sounds a lot like an out of adjustment throttle body, or bad TPS.. probably a bad TPS.

If you own a chiltons, haynes or FSM.. look up TPS or throttle body adjustment and give it a whirl.

GVOLCRunner

If you have a multimeter, you can check you TPS; you want to check the voltage across the terminals it controls.. among other things the idle fuel ratio correction; a.k.a brake applied idle at light; or in gear low rpm.

Kinda sounds a lot like a tps without looking and hearing it.

dahkodah

have yet to get a diagnostic run, but here is an update and more ?'s...the CEL is off this a.m. but still runs crappy...have been reading about the TPS and realized I accidentally took that off yesterday and put it back on without any change...which leads me to one of my questions--my TPS has only three pins in the harness and the screw holes are round and do not have any "adjusment" capabilities once the screws are in. this is a 98 V6 4WD...am going to try and get the diagnostic done today, but any ideas or info on the TPS...maybe a bad fuel filter...still trying to think cheap

dahkodah

ok here are the two codes I got...P0300 and P0306 which look to be a misfiring 6 cyl. just to be thorough rest of scan showed the mil fxn off and the monitors where 3 incompletes the catalyst, EVAP and o2 sensor...which cyl is 6 and what is my next step?

dahkodah

when you hear hoof beats think horses not zebras...i changed out #6 and she purred like a kitten... oh well...changed the rest and we move on thanks for all the help and suggestions...still learned a lot