TBI Idle and Throttle Issues
 

Hey guys,
My 88 K5 Blazer has been running rough since I replaced the exhaust. Many posts out there are very close to mine, but I couldn't find one with the exact same issues. I use my truck for plowing, and I did some tune up work on it this year. So far I've done the fuel filter, EGR valve and sensor, fuel pressure regulator, and some TBI gaskets. After that, the truck ran amazing. Started righ up, idled and ran great. Then I replaced the exhaust, which was rusty, leaking, and falling off. Now whenever I start the truck, I need to keep my foot on the accelerator to keep it running. When I let off, it begins to idle rough and soon stalls. Also, when I attempt to rev the engine, it chokes out and responds terribly. It also blows white smoke from the tail pipes now. I cut the exhaust off before the cats, but they weren't attached to any sensors. Not sure how changing the exhaust would cause all these problems, but I'm running out of time before the snow hits. Hopefully someone here can offer some ideas.
Thanks!

could just be a weird coucidence. disconnect the exhaust off the manifolds and see if it still runs like crap. possible there was something in the new pipe, maybe a rat went in there and died or something. or if it has a converter it may have broke and clogged the system.

dodge ram came into work the other day and thats what happened, couldnt rev it up over 2000rpm. drilled some holes in front of the cat and it had a ton of power back. honeycomb inside cracked and clogged the pipe somehow

Thanks, ill give that a try. I cut off the cats, but it's possible something got in the tailpipes between the time I cut them off and replaced them with new ones. If its unrelated to the exhaust, any ideas what else it could be?
Thanks!

Looks like the IAC went bad while I was working on the exhaust, so it was all just a coincidence. Replaced the valve and it runs much better.