1994 4runner 3.0L


Starts fine, idle picks up normally to about 1100-1200 RPM, then after approx. 1 minute as temp increases idle bogs down to 400-500 RPM for about 30 seconds, then rises back up to normal RPM range. I have noticed if I drive it prior to the idle settling fuel economy and power are reduced. If I let it get to normal operating temperature the thing runs great. I suspect something in the EGR system, but not sure what would cause this particular problem.
Any ideas where to start testing?


Thanks in advance

 

Ignition timing. Vacuum leaks. ECT (engine coolant temperature) sensor.

(Do the easy stuff first.)

 

Thanks for quick reply.
Timing is good.
No apparent vacuum leaks, all hoses look in good order with no cracks etc.
I'll check the ECT and see if that's good.


Thanks again