Originally Posted by sraab928
They did say they hooked up the reader and got no faults.
I think the potential fixes which Brad and Bob are suggesting are both straightforward and low cost/effort, so sound like worth pursuing, certainly before getting into the business of a TBI/sensor rebuild. That isn't expensive in itself, but it takes time to get all the right bits and strip it down. I think some of the vacuum lines were hard to get hold of, but old new stock was kicking about on ebay. When I had the TBI rebuilt, I also took the opportunity to replace the IAC value, TPS sensor and vacumn lines so I know it is all new stuff and kept the old for spares. From memory, I think some of those can get sticky and give intermittent issues.
Detailed Service manuals here:
Suggest you check through Driveability symptoms here (section 2-12):
2-12 DRIVEABILITY SYMPTOMS
HESITATION, SAG, STUMBLE
Definition: Momentary lack of response as the accelerator is
pushed down. Can occur at any vehicle speed.
Usually most severe when first trying to make
the vehicle move, as from a stop sign. May cause
the engine to stall if severe enough.
• Perform the careful visual/physical checks as described at start of "Driveability Symptoms,’
• CHECK: Fuel pressure. See "Computer Command Control,” Section "3”.
• CHECK: Throttle Position Sensor (TPS) - Check TPS for binding or sticking. Voltage should
increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT).
• CHECK: MAP sensor response and accuracy. Use MAP sensor output check in "Computer
Command Control” Section "3”.
• CHECK: Water/Contaminated fuel.
• CHECK: Cannister purge system for proper operation. See "Evaporative Emission Control
Spark plug wires for being faulty.
Spark plugs for being fouled.
Open ignition system ground, CKT 453. See "Ignition System/EST,” Section
Ignition timing. See "Vehicle Emission Control Information” label.
• CHECK: For correct PROM/MEM-CAL (see Service Bulletins).
• CHECK: Generator output voltage. Repair, if less than 9 or more than 16 volts.
• CHECK: EGR valve operation. See "Exhaust Gas Recirculation (EGR) System,”