Surging

I have a 01 tacoma 2.7L
When cold, at just off idle ( in park ) the rpms surge up and down very lightly, in gear , if I accelerate
Slowly it will surge to a certain rpm and the it will take off quickly, also will surge under load in passing gear.
After driving 25 miles , it is a lot worse . I have replace TPS twice ( one OE and one aftermarket) and
Replaced MAF twice ( same as tps ) replaced coils, plugs and idle air regulator twice ( same as tps ).
Took it to a shop and they was unable to find issue . It is not pulling up any codes. If I get on it hard from dead stop it will surge a little. If I ease it to it. It starts bucking (hard surge )

 

Did you replace wires?

 

Does not have wires. Coil packs. And I did replaced them. I was thinking it could be a transmission problem
but the shop says they don't think it is.

 

Spark plug tube gaskets, maybe.

 

Mmm ? Interesting, I wouldn't have thought the tube gaskets would have anything to do
with driveability issues. I am willing to try anything at this point.

 

Ya, me either. Good luck.

 

At idle is it fluctuating overall higher rpms than normal?


I almost wanna guess vacuum leak.

 

Idle is good. About 1100 rpm ( In park ) it's pretty faint . Under load is when I feel it. But real bad after driving far 25 mins or so .
Really a lot worse under load

 

Mine idles at like 750, so that seems high to me. But i dont have an auto.

If you scan it are there any pending codes?

 

No codes and idles at 650 or s
O

 

It surges like a race car that has a Rev limiter .

 

Well, I got an update on issue. I had a shop look at it and they could not find a fix and then took it to the dealer and
$650 later. They could not find anything. Good compression, good vacuum , no exhuast leaks , fuel pressure is 46 psi.
Compression is 180 ( 1,2,3 cylinders ) 185ish ( 4 cylinder) I haven't done a valve adjustment yet. Replaced tps , maf, iac.
With aftermarket and then new OE , new coils & plugs.
I'm still getting a slight up & down idle and at 1100 rpm it acts lick a Rev limiter ( pretty heavy up and down surging )
And at 2200 rpm while trying to pass someone it surges when you get into passing gear. After getting back from dealer. It's worse.

 

My vote would be to check hard for vacuum leaks

 

Def sounds like vacuum leak in my limited experience. Very odd about no code tho.

 

You don't state what transmission you have. But in a later post you state that the truck surges also when you hit a passing gear or try to pass someone. I had this problem and the root of it was old fluid in my automatic transmission. After several pan fluid changes this fixed or greatly reduced my surging in passing gear problem. Maybe you have a compound problem or several issues.

 

This sounds more like a worn throttle body to me.