I just bought a 89 iroc with a LB9 and 700R4 with 140k miles. When I start the car up it runs great but when I put it in drive or reverse it bogs down really bad. What do you think it could be. A couple guys at the local chevy dealership said it was the cat.

 

come on now guys. I know some one has a idea or opinion on this.

 

Your not getting that many responses because it's only been a little over an hour since you first posted. Anyways, it's too hard to pinpoint what it could be by just that. If your catalytic converter was clogged that bad it wouldn't even idle, let alone start. Do you smell anything strange when the engine idles, similar to a rotten egg scent....?

Did you scan for codes? How is your TPS setting? Did you clean out the throttle body? Replace your IAC? Run a vacuum test? How's your fuel pressure? Are you getting spark to each and every cylinder? These are just some of the things you'll need to cover first before member's can make a valid suggestion....