1998 4 dr Chevy Tracker 4x2 1.6L-16V
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I was driving and my check engine light came on.  I continued to drive it home on the highway.  I was doing about 60mph and the rpms started jumping up and down slightly, then about 2 minutes later they just jumped way up like it came out of gear.  Now it doesn't want to go in to 3rd gear, but if I hit the overdrive switch on it will try to go into gear and the rpms will return to normal but they jump right back up again.

I took it to Autozone to have the OBDII codes read and got the following

1.) P0751 Shift solenoid malfunction
2.) P0510 Throttle position switch malfunction

The guy at Autozone said that a bad TPS could cause the solenoid error and not make it shift right.  I have read about the TPS and it apparently sends a signal to the ECM which controls the torque converter, which controls shifting.

Do you think that the TPS could be causing shifting problems?  or Do you think it is something else?  Any information would be helpful. 

I will pos more later.  I have to get to work.

THANKS

the easiest way to test the tps is to get a shop book or a wiring diagram to figure out what wire is the sensor output. the tps will have 3 wires - 5 volts in - a ground to ecm - and the output. turn on the ignition and put a multimeter on the output wire. it should read about .5 volts when the throttle is closed. slowly open the throttle watching the meter. it should slowly go up to about 4.5 volts at wide open. look for any drops or glitches in the meter as you do this. any drops or cutting out means you need a new tps sensor.

derek

The TPS has 4 wires because it is combined with the idle switch. The TPS should sweep progressively between a fairly low resistance and around 6.8KOhms. I worked on Tony Bennet's Suzota the other week, it was throwing a TPS error but it was a broken wire between the TPS and the ECU.

Do you think that the TPS could be causing the shifting problem?

Do you think that the TPS could be causing the shifting problem?

absolutely ... especially with the codes being thrown.

One thing to consider is the TPS might still be good, but a broken wire or ground.

It's threads like this that first got me hooked on this site.  No definitive answers, necessarily, but several highly educated and specific opinions/takes on the situation.  You guys rock.