I am currently having issues with my motor backfiring though the intake right off idle. When you blip the throttle from idle or give it just a bit of gas on the road it will backfire. It idles strong and runs strong but the problem has been there for a while, and is getting worse and worse. I am wondering if an extreme rich or lean condition could be caused by the TPS. Also does anyone have instructions on how to check the sensor? Can you do this with a simple volt meter?

I know this problem could be a valve not closeing issue as well as other things and I am tring to track it down (mechaniclly and electriclly). This problem has been present since I rebuilt the motor, but at that time it was hardly ever backfiring (now it's almost allways doing it)

Things I've tried include:
Reajusted the valves many times using mutiple preloads. From .03"-.06" (OEM standard lifters)
Replaced the ICM
Replaced the Coil
Replaced plugs and wires
Tripple checked plug wires match up
Replaced Opti and then ran the old opti to see if it still backfires.
Shut down one cylinder at a time (by grounding the spark) and problem was present every time
Checked the vacuume (15 in at iddle)
Checked fuel pressure at WOT on the road (43 psi)
Pulled the intake manifold and had it machined to match the motor (Vacuume still at 15 in)

At this time I'm desprete enough, I might even take advice from my wife!

Thanks

 

Assuming you don't have a DTC 21 or 22, measure power and ground from the black to the grey wire at the TPS. Should be 5 volts. Now measure from the blue wire to the black wire as the throttle is moved from idle position to WO. The voltage should vary from about .5 or .6 to about 4.9. First check the 2 extremes then go back and move it slowly from idle up to WO. Look also for spots where the drops out more than likely.

Because of the nature of potentiometers, they will wear frequently. They're darn near considered "tune up" items.