Toyota Repair: 1990 4Runner 4 cyl Surging Idle, air flow meter, egr system

Question
I recently purchased a 1990 4Runner with 271000 miles and the 4cyl with a 5 speed.  When the truck is first started the idle is great.  After it warms up, the idle surges between 1200-1500 rpms if my foot is not on the brakes.  If I have the brake pedal depressed, it surges between 750-1000 rpm.  The computer has thrown one code, 71.  I have sprayed carb cleaner around all the vaccuum lines that I could find and it did nothing to the idle speed.  I also sprayed a little carb cleaner in the EGR in case it was caked up a little.  I've heard to replace the Air Flow Meter but hate to throw money at it in hopes of finding the correct issues.  It seems to be a little underpowered, but I'm use to big block V-8's, so I'm not sure if it is or not.

Thank you,

Joe

Answer
The code#71 is related to the EGR system and it sounds like the EGR valve may be hanging up and causing the idle problem, it's not the air flow meter! Try replacing the EGR valve and the modulator valve and make sure all the vacuum lines are installed correctly, that should solve this problem.