I keep getting an EGR system malfunction code 71 and it runs like poop at idle, sometimes at a stop light dropping to 500 rpm. I have replaced the EGR valve with a Toyota Denso EGR valve. I was also getting a code 41 TPS circuit and code 26 mixture adjustment excessively rich. I had a vacuum leak from the EGR pipe at the back of the intake from missing a bolt on one side of the pipe and after I got a bolt for it and tightened it up I got the code 26. I adjusted the TPS (I did replace the TPS recently when I was trying to track down another problem) and then I cleared the computer and the code 26 hasn't come back yet after driving it for a day neither has the TPS but my EGR malfunction code did come back. What could cause this? I'm thinking about buying a modulator, sensor, and tvv from a yard.

 

Check all the vacuum hoses associated with the EGR and also the small metal pipes that run from the TB to the rear of engine can also become clogged.
Blow air thru all hoses and lines to be sure their clear.

 

If you want to throw parts at it, that sometimes works. Not very often, but sometimes.

What does the manual suggest? http://personal.utulsa.edu/~nathan-b...26diagnosi.pdf I'd start by checking the gas temp sensor and working back from there. (You'll eventually get to checking the vacuum lines as SoCal4running suggests.)

Keep in mind that the "parts" might not be the problem; if your gas temp sensor wire is broken (or unplugged) you'll get that code.

 

Delete it i did on mine and its runs much better and get better fuel mileage