So still have some strange issues with the Blazer and getting really tired of it but...oh. Now when starting the engine will run up to about 1700-1800 RPMS and then come down and stays around 1000. After reading a bunch of other threads I am going to try cleaning the IAC and maybe replacing the TPS. Just wanted to confirm via a pretty picture if I am looking at the correct items. This is a 95 Blazer with a W vin code.

 

You got it!

 

Yup IAC & TPS also look at EGR systems.

 

Unless you're getting a DTC for the TPS, and following the flow chart specifically instructs you to replace it, leave it alone and save your money.

 

You can test your TPS with a volt meter, too, can't you? I think I remember doing mine a while back. Basically you want to see a smooth ramp up and down, no jumps or missing spots.

 

Yup, voltmeter works, and so does an ohm meter. If there's a dead spot, the PCM will let you know too, it constantly monitors TPS.

 

Cap on it again.

To test it, have the truck off, and take off the harness from the TPS (I do not remember which wire is which honestly to test it... CAP knows)
But with it off, put the positive lead on one wire, the negative/ground on the other, and slowly open the throttle by hand with the DMM set on Ohms.
And watch the ohms rise (VERY SLOWLY open it)
the ohms should rise smoothly until its WOT (wide open throttle) then you slowly close the throttle and watch the ohms drop back down smoothly

Now ohm values are not important, its how smooth they go up and down.

If there are any dead spots, points where it jumps around would be an indication of a bad TPS


My truck threw a code a month ago when everything decided to go bad at once, so I tested the TPS.. and it literally went from (numbers are not what they were, just there for example) 1000ohms to 3500ohms in about 1/4 of throttle, and kept on jumping from high to low through the whole.

 

Here's how I tested mine: Part 1 -TPS Test: GM 4.3L, 5.0L, 5.7L (96-06) P0121, P0122, P0123.

Just a different way of doing the same thing as rich posted above

 

What is the best way to check for a vacum leak that could be causing the high idle?

 

lightly spray carb cleaner around the engine bay while the truck is running, and listen for the idle to change.