Fluctuating idle and bucking when driving

Hey guys so I’ve made this post before but I have an 01 SR5 and it was running good then all the sudden it started with the idle fluctuating between 600-800 rpm and shifting into 1-3rd gear it bucks (occasionally). I’ve hooked it up to a scanner and everything looks great so I’m at a loss

 

I would check these three things. MAf Sensor, Trans Fluid (When's the last time you did a flush and drain?), and your throttle body. Check the throttle adjuster. I would remove your intake, get some throttle body cleaner, some plastic brushes and rags. Clean the carbon up. This is the cheapest and quickest way to do it.

 

I will try that today, I replaced the MAF but I didn’t mess with anything else

 

I had a friend who's '98 Tacoma SR5 (V6) had similar symptoms. His were resolved with a new TPS, and new fuel injectors. We did both at the same time and so we can't be sure which of the two solved it.

 

How old are the spark plugs?

 

I haven’t changed them but they looked good when I pulled them

 

I just ordered my TPS as a shot in the dark so hopefully that will fix it

 

OEM Toyota hopefully? You can easily check yours with a multi-meter. The FSM has a testing procedure outline in it.

 

Yes I ordered OEM and put it on( I also cleaned the throttle body while I was there) and it seems to be idling somewhat better but it is still bucking

 

Could be your injectors then causing the bucking. Have you been able to identify an RPM range the bucking occurs in? My buddy's only bucked between 2000-3000 RPM, above and below that range it ran perfect.

Also have you scanned for any codes?

 

Yes that’s the same range mine is bucking, and yes I’ve scanned it a few times and I haven’t gotten a code

 

If it's a 4 cyl and the valves haven't been adjusted then that's a problem waiting to kill the engine.

 

Any ideas for where to look if it’s a 6cyl?

 

Leaning towards your injectors since it's mirrors my buddy's previous issues. But any history of touching your IAC?

 

I haven’t messed with the IAC I had just thought it would be throwing codes if it was that

 

I had a ‘97 4Runner with that same 3.4L engine. It acted exactly as yours did. I finally replaced the coolant sensor on the middle front of the intake manifold for like $20. That thing was giving whacked information to the computer which wad screwing with idling and stalling. It’s easy to replace with little to no additional parts needed removed. I would try that.

 

If the idle is still not perfect and you have no vacuum leaks, then I'd start with carefully trying to clean the IAC. If idle is good I'd focus on cleaning or getting new OEM injectors

 

Thanks I’ll try that!

 

I will try to clean it tomorrow, thanks!