Lean Idle...Help

[flashinthepan]

New here,

I have a 98' 4-runner, in which I purchased brand new. The vehicle now has 71K miles and just rec'd a new factory rebuild on the 3.4 6 Cyl engine. The SUV has been flawless in everyway, then 1 hot summer day a main bearing failed (under the extended warranty-whew!).

So dealer rebuit etc etc.

Problem:

When in drive and idling at a stop-light, she is not smooth like the original motor ??? Feels slightly shaky and appx 200 RPM's lower than ideal.

Have had it back to the dealer twice, they agree it is not as smooth as others, but no fault codes ?? and that they cannot reset the OBD to raise the idle or richen it ????

ANY ADVICE ?????

Sincerely speaking I am out of options it seems ......

The Factory mechanic said there are no vacuum leaks and have testing everything ??????

 

[TSP-MIKE]

First of all are you sure they rebuilt the 3.4L? Because Toyota does not make any rebuild kits for those motors.

For the the low idle and shaking, check the spark plugs and the wires. They might not have put new plugs in. These 3.4L's are known for low idle's but not the shaking

Mike

 

[flashinthepan]

Thanks Mike,

The dealer replaced the shortblock with a factory one, rebuilt the heads and replaced all the exterior parts with the original ones. The plugs were replaced at the time of the rebuild.

The new motor actually has noticably better power and runs absolutely great ! except the condition of

Being in drive and waiting at a stop light...it shakes and seems lean ?

Its crazy ! the mechanic has said a few times that he even wishes the idle had more inherent adjustability & it is impossible to fool it into a richer mixture or slightly different idle speed.

I also asked if in fact slightly larger jets were available for the fuel injection system...the answer was no ?...wouldnt it seem that if you rebuild a motor to slightly increased specs..that one could either adjust the mix or get larger jets...??

This does have even the factory mechanic somewhat baffled, they even called Toyota N.A.....

Is this crazy or what ??..lol.

Perhaps "I" should relace the plugs again & even get new plug wires and or a coil ??...the parts would not be too expensive, and perhaps worth the try ???

OH BTW if you are in drive and apply the brake (while at a full stop) you can give it slight gas, say an extra 200 RPM's and she smooths out nicely ??? furthermore when in park and at idle it is very smooth as well....

:arrow:

 

[TSP-MIKE]

Try checking your brake booster. It might have an internal leak and will cause the engine to loose vacuum.

Hope this Helps

Mike