Dylly

This is my 1993 short box, reg cab, 2wd toy truck that I only drive in the summers. So I took the truck out for the first time a day ago... ran fine, shifted fine until i fired it up this morning ...

Wants to idle at ~1200rpm... when it tries to idle down, it attempts to die and surges up to ~1200rpm again ... Changed the idle air control (IAC) sensor out... same thing still ...

Took it out for a drive and it refuses to shift unless you let your foot off the throttle... Held it at 2000rpm and wouldn't shift out of first without letting off the throttle.

Could these two symptoms be related? and/or what could my problem be?

shamrock246

check the TPS and see if there are any vacuum leaks,are the IAC passage ways clean


Sean

97 4x4 burb

Dylly

I'll check the tps shortly... I did take the throttle body completely off and clean where the IAC sits and the passages so those look fine. As for vacuum leaks.. I sprayed ether all over the place and no noticeable change in idle... although it has a hard enough time as it is.

The thing that bothers me is that its affecting shifting as well... Is the TPS involved in shifting on these OBD1 vehicles?

Dylly

Well good news! Changed the TPS and it shifts and idles like it used to.... I guess the TPS operates how it idles and is used to determine shift parameters by the ECM.

Either way... Its nice when the first suggestion works.

Thanks a lot!