After swapping in remanufactured heads on my 1986 Firebird SE, I reassembled the engine and was leaking coolant at the throttle body.

I took the throttle body off, created a new seal using some compound, and put the throttle body back on.

It no longer leaks coolant, However, when I was mounting the throttle body back on to the plenum, I had one of the bolts cross-threaded. I didn't realize it until the plenum literally cracked at the hole; it's about a 2 inch crack that runs lengthwise along the bolt, and the bolt isn't torqued down very well.

When I start the car, the engine is all over the place, at first to rich and then it stalls out. After repeated attempts, and manipulating the gas pedal, I can get the car to idle, but the computer keeps adjusting the throttle body trying to compensate--i.e., it keeps revving, then almost stalling.

I think what's happening at this point is that the bolt at the cracked side basically isn't torqued down enough to be air-tight, so air is getting into the engine just past the throttle, right where the throttle meets the plenum.

So, the question is, what can I do? Do I need to completely replace the plenum (good luck finding one)? is there any way to repair it with some kind of weld? Is there some sort of way to simply better seal the throttle body at the plenum so less pressure is needed?

Please help.

-Mark

 

best and probably cheapest bet would be to go to a junk yard and get a new plenum. or, maybe you can find somebody on here who has one for sale. I doubt you'll have any luck repairing that one (without spending more money than you would to replace it, anyway).

 

Been there and replaced that. The driver's side mounting ear (not just the hole) came off on mine and I had it repaired. The guy at the welding shop didn't do the job very well and I ended up using 2 gaskets to attempt to seal his mistake. I ended up replacing both the plenum and the throttle body with ones that went with my 3.1.

 

here's one I just saw

http://cgi.ebay.com/ebaymotors/ws/eB...l%3FMyEbayBeta

 

I've got one around I'm trying to sell, I'm assuming based on your profile picture/info that its a 2.8 you need, let me know if you're interested.