so i have a socketed p28 that i ran on my previous swap with no issues and the only thing i changed about this swap was a new bottom end. car was running fine with no issues on the obd2 p30 i used while i was breaking in the motor then i take it in to get dyno tuned (same place i went through before) and after the tune the car would randomly die when coming to a stop instead of going back to idle it would just drop down to 0 and shut off. took it back and the tuner said it was probably because the o2 was enabled or the fast idle thing so he messed with it a bit and it still did it so he burned me another chip with the o2 disabled and it doesnt die any more but in the mornings it idles kinda rough at 1k kinda chugging or something and in the mornings sometimes it throws a code 7 (tps) but goes away after i shut the car off and dont see it again till its cold again. what the hell is going on what should i do?? he is a reputable tuner and has alot of serious cars under his belt but everyone at the shop is stumped

 

Sounds like it could be a wiring issue...or a component issue.

If it is dying the IACV could be malfunctioning or dirty as this means it cannot keep up (Crome doesnt have the best idle control).

If it is only dying with the O2 enabled, then perhaps the O2 is malfunctioning and targeting either a too lean or too rich condition that is running the motor to the extremes of one of these conditions and causing it to die.

 

the only thing is if i pull out the chipped p28 and put my stock p30 in i have none of these issues so i dont think any of my components are bad it has to be something with the tune anyone ever run it to this?

 

The issue is not the software. It sounds like a tuning or hardware issue.

Concerning a code 7, this maybe the culprit. It sounds like your tps is providing the incorrect voltages to the ecu perhaps negative throttle position at an idle or stop.

Calibrate your tps & go from there.