Greetings I am a forum newb with a minor issue I am hoping to get advice on. I failed CA emissions yesterday due to higi HC @ 2650 rpm, at idle HC was higher than average but passed. Last week I had an issue with the truck (93 Sierra 2500 5.7) falling on its face off idle when driving, and loping off idle in nuetral. Since there are no trouble codes, I went ahead and replaced the TPS with intentions of doing the TPS and then the MAP. Soon as I replaced the TPS my truck idled 200rpm higher than it had been and the stumble vanished! I was pretty stoked since I just kicked Murphy and his law book in the privates =) So, a week later I am on my way to smog and she starts the same symptoms, but I figure hey they test idle and 2500 so shouldnt be an issue.. WRONG! when I got the truck and failed test back she was running just as bad as the previous week before the new TPS. So, my question is are the Duralast TPS realy THAT bad, or do I have a possible wiring issue that the fresh TPS simply worked with for a time? Right now every sensor except the MAP is under a year old. Thanks in advance for any ideas!