hey, my 4runner shakes only when i accelerate. it just started doing this out of no where. it's a 1998 3.4L, 2WD. things i've done so far:
1. got brake rotors turned (they were badly warped) so thought it was a possibility
2. replaced spark plugs, air filter, put in some fuel injector cleaner
3. finally took it to a mechanic to run some tests and found the O2 upstream sensor to be reading off.
that was the only thing he was able to find after testing the coil overs, inspecting u joints, and got some other readings but everything else was fine. i replaced the O2 sensor and it's running better but it's still shaky and don't want this to become a big problem. i looked up on advance's website where you can click on symptoms you have and it tells you what the problem might be and it says i need a new TPS but when i googled the symptoms for a bad TPS, i don't see anything like mine. tranny fluid's good, oil's good, everything seems good. what the mechanic didn't notice and i forgot to bring up, was when you put it in reverse, it shifts hard. also only a couple of times during the summer, the engine cut off after idling for a while with ac running but was able to start again right away. i'm new at this and googling my way through this so if anyone replies, please explain as if you're explaining to a child, thank you!
1. got brake rotors turned (they were badly warped) so thought it was a possibility
2. replaced spark plugs, air filter, put in some fuel injector cleaner
3. finally took it to a mechanic to run some tests and found the O2 upstream sensor to be reading off.
that was the only thing he was able to find after testing the coil overs, inspecting u joints, and got some other readings but everything else was fine. i replaced the O2 sensor and it's running better but it's still shaky and don't want this to become a big problem. i looked up on advance's website where you can click on symptoms you have and it tells you what the problem might be and it says i need a new TPS but when i googled the symptoms for a bad TPS, i don't see anything like mine. tranny fluid's good, oil's good, everything seems good. what the mechanic didn't notice and i forgot to bring up, was when you put it in reverse, it shifts hard. also only a couple of times during the summer, the engine cut off after idling for a while with ac running but was able to start again right away. i'm new at this and googling my way through this so if anyone replies, please explain as if you're explaining to a child, thank you!