I appreciate if someone could help me to diagnose the following symptom on my 89 Toyota Pickup, V6, 5spd, 4X4.
When gas pedal is slightly pressed, the check engine light will flash once quickly, and the engine will hesitate/stall when the flashing happens. After accelerator passes that slightly pressed position, the engine responses normally. Checked idle speed and timing, both are fine. Tried to read out error code from computer, if the accelerator fully relaxed, the check engine light flashes steadily, which means no error codes; if the accelerator if pressed, there is a 51 code, which indicates a faulty throttle position sensor. Checked and adjusted TPS several times (in specifications after adjustment), the symptom remains the same. In the end, I pulled off the connector of TPS, the symptom is still there, not better, not worse, can't tell any difference.
I have the following questions,
- Should I press accelerator when reading error code? In other words, is the 51 read out while pressing accelerator valid?
- What would be the effect of running engine with TPS unconnected?
leaning to replace TPS, but would like to have evidence showing the TPS is dead.
- To me, the problem seems to be related to throttle position or RPM. If is not due to TPS, what else could go wrong, and how do I test?
Desperately looking for a clue. Thank you.