I have a '93 LT1, and I'm having a problem that's bugging me out. It's an intermittent problem more or less, but it's consistently intermittent, if that makes any sense at all.

The speed of a car engine (in RPMs) normally corresponds almost directly to how heavy your foot is on the gas pedal.. That's an engine that's working properly.. But mine isn't really working like that.

Basically, it's having episodes when I'm driving where if I step on the gas to accelerate (meaning anything more than coasting throttle), the tachometer drops like a rock to what appears to be zero RPMs and all engine power cuts off until I let off the gas. Then it goes back to it's coasting RPM. For some inexplicable reason, the engine never stalls when this happens, but I would have to call that a huge positive in this situation.

It never seems to happen when the amount of throttle being applied is anywhere from about 0-15%, but it does happen both at highway speeds and when trying to accelerate from very low speeds (~ 4-10MPH).

The reason I think it might be the TPS is because I recently replaced it, and I haven't had the TPS re-learn procedure done as the service manual instructs. I was also having some fuel pressure performance issues when I replaced it, so I can't tell if the TPS is what's causing this, or if it it's a separate issue that was being masked by the faulty pressure regulator. It is throwing ECM DTC 22 (Low TPS Voltage) and ASR/ABS DTC 64 (TPS Signal Malfunction), but will the re-learn procedure really fix a low voltage reading? Does anyone out there know a little more about what exactly the Tech-1 does when it "re-learns" the TPS? And besides that, does this problem I'm having sound like something the TPS could do? What else might it be? Someone please help me.. before I

 

Was the problem present prior to the TPS swap?
If not, I would put the old one back to see what it does.
If the same, take two needles, and push them through the isolation of both 2 top wires and check voltage with ignition on (don´t get them touch each other), connector on the TPS.
See for anything between 0.3 and 0.9 volts.
If so, raise the throttle (engine off) and watch the volts rise steadily up to 4.5-4.8 volts.
If not, check if the pins in the connector are in place and tight and cannot move while you put the connector on.
If they are not tight, you will get these kind of glitches.

Just a free check, and if it has worked OK once, and didn´t do anything else to the wiring, I would start there.

 

I would bet it's the fuel pressure issues causing the problem. My 86 was doing exactly the same thing, and I found out it was a bad pump. Screw a fuel pressure gauge onto your schrader valve, and tape it onto your windshield. take the car for a drive, and see if the pressure drops. When mine was doing that, the pressure was at 13 psi.