1991 3.0 time for a valve job?

[bigrod00]

I have a rough idle and bad gas mileage on a 5 speed 3.0. I have checked for vacuum leaks cleaned air filter, PVC valve good. I am not getting any check engine light. I am suspecting a valve issue??? I recently purchased this unit for quite cheap. The previous owner had a compression check and he had lower #6 compression. It had 329,000 kms on it. It does not smoke or steam, overheat and drives better at higher rpm. Oil is good color and antifreeze stays full. Am I in for a head job or can it be something simple? Any help would be greatly appreciated. I have also tried adjusting timing and idle. Intake manifold appears to fine and no vacuum leaks. I reset computer and rough idle still there. Intake from air cleaner to fuel injection good. It has a new timing belt job by Toyota very recently.

[jetwhine]

bigrod00,

With that many miles it might be time to clean the throttle body. It might also be a sticking EGR valve.

[bigrod00]

Originally Posted by jetwhine

bigrod00,

With that many miles it might be time to clean the throttle body. It might also be a sticking EGR valve.

What would you suggest cleaning it with? Romove intake and spray down with cleaner or can I do it on truck?

[jetwhine]

bigrod00,

I would take it off to clean it. You can do a much better job if it is off. Also while you have it off you should check the TPS throttle position sensor idle setting. It is done with a feeler gauge. I would use Isopropel alchahol it works great and leaves no residue and is cheap to purchase.

[ZARTT]

How low was the compression in #6?
The reason I ask is because #6 is the cylinder where the head gasket usually fails if it is going to, on a 3VZE engine.
The exhaust from the odd cylinder side of the motor crosses over the bell housing through a pipe, and meets the exhaust from the even side of the motor right in the area of #6.
The driver side rear cylinder (#6) has the heat from all 6 cylinders concentrated in that corner of the motor.
You might want to investigate that possibility.

Art.

[bigrod00]

Originally Posted by ZARTT

How low was the compression in #6?
The reason I ask is because #6 is the cylinder where the head gasket usually fails if it is going to, on a 3VZE engine.
The exhaust from the odd cylinder side of the motor crosses over the bell housing through a pipe, and meets the exhaust from the even side of the motor right in the area of #6.
The driver side rear cylinder (#6) has the heat from all 6 cylinders concentrated in that corner of the motor.
You might want to investigate that possibility.

Art.

#6 valves not sealing. I will be replacing heads on weekend when gasket set arrives.