Hi, my 99 Blazer intermittently drops the reference voltage to the throttle position sensor.when the truck goes into closed-loop mode it tends to act like its running out of gas fuel pressure test came back good. runs fine when open-loop mode but the minute it goes into closed-loop mode I have stuttering issue.has anybody had this problem I'm at a stop getting very impatient with it replaced a lot of sensors already. could I possibly have a bad computer