2.7L engine high idling help!!!

I have a 1996 Tacoma with the 2.7L engine. When I have the truck in neutral the engine stays at a high idle or it fluctuates from a regular RPM to high idle. This happens when its just sitting there idling and as I'm driving and push in the clutch. If anyone knows how to fix this problem please help me out!!!

 

Check if there are cracks on the intake tube leading up to the throttle body. My old ford explorer used to do what your truck does; It was from cracks on the intake tube.

 

First make sure the throttle is closing completly , nothing hanging up the throttle cables or pedal, check that all the vacuum hoses are tight , no obvious vac leaks , a tiny vac leak will raise idle a large leak will cause a stall or stumble

next check and or clean the idle air control valve (IAC) .
it is located under the throttle body
most common cause of idle problems and first thing the mech will check
the IAC is a drum shaped valve on a magnetic switch that is electrically controlled by 12 volt signals from the computer when engine is cold it switches trough a relay to allow more air intake that raises idle speed, a weak spring keeps it in normal position , the ECT (engine control temp) sensor tells the computer the engine is cold and sends 12 volts to open the IAC , when ECT warms it shuts and the spring takes over
if the IAC gets sticky it could keep idle up

to get to it : first remove the air filter cover, unplug Mas air flow ( MAF) sensor then two bolts under the resonator box and remove the entire air intake
at this point you can try spraying carb cleaner in the TB (throttle body) which should do it
it probably wont run with the intake off because the MAF sensor in the air filter intake will not get a signal

another hit and miss way is to just remove the intake at the TB to the side slightly while reving the motor at the throttle and spray Sea Foam brand spray into the intake as it is running to clean it out

or continue to remove the TB and throughoughly clean
unbolt the throttle body, pull it up a little to make it easier to get to the plugs and hoses
unplug the TPS (throttle position sensor) and IAC plug
then remove the vacuum lines , throttle cables

removing the IAC from the TB can be difficult because it has phillips screws, a hammer operated impact driver works to get these off
clean it all out with carb cleaner
the kweer shaped Oring gasket is very sensitive and should probably be replaced avoid carb cleaner on it
may also want to replace the TB to intake plenum gasket
not usually a problem but the IAC an be tested by jumping it to 12v , positive to middle terminal , neg to each other 2 terms
avoid getting carb cleaner on the TPS
it is slightly possible that the TPS could be at fault but less likely and a failed TPS would probably leave a check engine light code (CEL)


report back and let us know what you found so we can learn from it

 

Check TPS, check the "coil on plugs" Peace

 

96 probably has a distributor

 

Ok Ill try these tips and see if I can fix it, Thanks for the help guys ill keep you posted

 

x2...
OP check IAC and clean TB also check ETC if it is not fried. Check resistance of ETC and resistance against ETC body. If resistance in ETC is less then 10 ohms against body you need new ETC. FSM has checks but they dont have one for ETC body. They just tell you to check internal ETC resistance.