I recently took my Mitsu in for smog and it failed. They said it was a bad egr. So I replaced both. Then after about 10 miles a new code came up so we replaced the Idle Air Mixture Sensor. Now the truck will start and it idels at about 800. When I puch the gas it bogs down and sometimes dies and sometimes catches back up. This led to the MAF weak signal code. So we replaced the MAF sensor. Now we are getting bad MAF, IAT and MAP sensors. Does anyone have any idea what is happening? It has 225k miles. Thanks in advance.

 

Time to stop and take couple couple deep breath. You are chasing electric gremlins. Do not throw any more parts at it. With the EGR - you said you "replaced both"... both what? EGR solenoid and EGR valve? Did you check if that system works after replacement? If you have a vacuum hoses incorrectly installed, PCM can get all sort of weird reading including mismatch of manifold pressure to the expected ingested air volume (hence MAF and MAP codes). This will also cause bad idle and thus IAC codes. Go back to the EGR and check to make sure it works. The way you do it is to put a vacuum pump on the EGR valve. With engine idling if you apply vacuum it should stumble and die. Without vacuum engine should run. If the valve works, check if you are getting vacuum in the hose going to the EGR valve (no vacuum or low vacuum at idle, higher reading with increase of engine RPM). Check to make sure you routed vacuum lines correctly. There are three ports on the intake manifold. They are not created equal. I don't remember which port EGR solenoid goes to, but if its on the wrong port it will not work correctly. Look for a vacuum diagram on the web and re-check everything.