I have been having a problem with my truck not feeling as powerful as I think it should be after a cam, 1.8 rockers, and a nelson tune(all at same time.) I thought it was the tuning that was the problem but that was ruled out when nelson sent me a stock pcm to put back in and it still does the same things. I swapped in several different pcms before trying the stock one. My Ltrims are about 12 bank 1 and 0 bank 2. I haven't been able to find any info on what this reading should be but the map reading is -8 psi at idle and falls to -0.7 or so at 65 mph. The timing at 65 is about 28*, sometimes less, and Nelson said that it should be between 32-40. It doesn't really feel as powerful as I think it should at any rpm or gear but it really seems to fall once it hits overdrive. Any idea where to start?

 

pull your fuel rail off and look in the end of the injectors

you are running lean on one side

 

I forgot to mention that I was having a problem with the idle when I get ready to stop. I would go dead if I didn't hold the gas some. I cleaned the throttle body and iac this weekend and the idle still fluctuates slightly but it doesn't go dead now.

What will I be looking for in the injectors?

 

buildup of any type. they should look really clean and have no residue on the connections

 

also you have a idle hole in your throttle body and sometime you have to drill out the hole for some more air to get in and you might have to reset your timing i think

 

Could the MAF meter be the culpret?
What about one of the two cats being clogged? Problems seem to happen quite often with the cats on the GM trucks and some cars.
Just spitting out some ideas that seem to make sense to me.

Jim

 

The idle problems may just be a simple adjustment of your idle airflow tables in the tune. I had to change mine all around when I did a cam swap.

 

cleaned your air filter recently?

 

I increased mine by a small percentage, and that cured my idle problems.

 

I cleaned the injectors and swapped sides with them. They didn't look dirty though. It ran a little better for about 30 miles and the ltrims were at 6.2 bank 1 and 0.0 bank 2. The problem didn't swap sides when I swapped injectors. After about 30 miles, the idle started messing up again and the ltrims went up to 10.1 bank 1 and 1.5 bank 2. I don't have any cats on the truck anymore.
Does the IAC have to do with anything other than idle? How do I know if it is bad?