I am borrowing my dads Jimmy until my AC is repaired tomorrow. He had his SES light come on so I told him I would take it to get scanned. He gets three Codes, the first two might be linked I assume.

P0121
P0300
P1870

The P1870 I don't think is what is described in the TSB. His has a hard time shifting from first to second. This does NOT happen every day. It comes and goes. After it warms up...it pretty much stops. Silenoids???

 

That's how the P1870 starts out... it gets progressively worse.

The P0300... start with the cap and rotor. Then i'd go to plug wires. Sometimes it can be injectors or a few other things.

The P0121... throttle position sensor. That's an easy one to replace.

 

I see where some buy a kit...but it looks like this doesn't require a total rebuild...just a replacement part...