83 GMC 2.8 guru needed please

I hope this is an easy one,carbed V6 codes 21 and 45 are stored.21 is an idle switch?45 is a rich code?Anyone hit this code combo and know the problem part?Thanks this forum and to all.

21 - TPS voltage high
45 - O2 sensor sensing rich.

Replace the TPS, and tuneup your engine fully.

Thanks very much for the reply,once I started typing this question I realized i was in the Blazer forum,i figured what the heck same thing as what I am working on,what this is ,is a 83 s15 pick up.I brought this up because if this carbed 2.8 has a TPS switch I cant find it.Is there a chance the 83 carbed 2.8 doesnt have a TPS switch.Thanks again.

Ok,went on napa on line seen the TPS,I will remove it and inspect it and then replace it tomorrow.And then report back thanks for your help.

No problem, glad to point you in the right direction.

Remember to replace the following for a tuneup.

Plugs gapped properly
Cap and Rotor
Check and adjust timing
Wires may need to be changed, check for condition and look for cracking.
PCV valve
Fuel Filter
Air Filter

I put a volt meter on it,suckers stuck open,I called all over town nobody has a TPS not even the dealer.I will open it up and maybe get lucky and be able to clean it. I have to take the top of the carb off to get to it.That looks like a pain.Thanks again.

TPS is not really a serviceable part.

You da man!
I ended up robbing a TPS from a 84 s-blazer and its fixed,easy to remove the top and tip it up without removing all the linkage.I bought this blazer cheap,not running well,I need to figure out the code 41 and buy a TPS I stole from it.Any help would be appreciated,nice to know the pro makes himself availible on this forum(BLAZE LT).Have a good eve.ThanksGonz

Code 41 is for an Throttle Position Sensor signal.

So that means it can't see the TPS you removed from it so it is throwing that code.

So the first truck is now running fine?

Yes the first truck is running better,never was all that bad.The TPS in that truck was stuck at 5 volts testing with a volt meter,I tested the TPS on the Blazer before I pulled it off,key on .5 volts ,throttle moved the volt meter right up to 5 volts,and now it does that on the first truck now that its installed,so I was getting a signal on the blazer as though it was working correctly.I am all ears,thanks for your help.



The first truck has not thrown a code since.

So the TPS on the first truck was replaced by the one you found on the second truck.

Where is the TPS on the second truck?

So the TPS on the first truck was replaced by the one you found on the second truck.

Where is the TPS on the second truck?




Yes the first truck (s15)got the TPS from the second truck Blazer.
GMC had codes 21,45

84 blazer has code 41

Ok, so the Blazer no longer has a TPS installed?

Ok, so the Blazer no longer has a TPS installed?
Right now the Blazer does not,it still has the top of the carb loose until i get a TPS. The code 41 was pulled a week ago from that vehical.

Well then that would explain the code 41, the ECM cannot find the TPS.

That is what code 41 is for.

It can't see the sensor you removed from it.

Well then that would explain the code 41, the ECM cannot find the TPS.

That is what code 41 is for.

It can't see the sensor you removed from it.

I am sorry I have totally confused the issue,the 84 blazer was showing a code 41 before anything was touched on it.

Sorry I totally confused the issue,the code 41 was pulled before the anything was touched