Starts, dies, warms up a bit and runs

[mr-natural]

The title says it all. I'm in AZ so it's not cold and the engine starts fine but will die immediately unless lots of throttle is applied and the throttle feathered to keep it from going too high in the RPMs. After maybe a minute or so the engine runs OK - not great. While trying to keep the engine running when cold there is occasional backfiring through the MAF. Once the engine is idling then it may back fire when applying throttle. TPS, idle and timing are all to spec. Any suggestions?

 

[Robertwav1]

You didn't tell us the year. I know mine the pintle valve that controls air in the throttle body (IAC) I guess it's called was dirty. Lot's of carbon buildup.

 

[mr-natural]

You didn't tell us the year. I know mine the pintle valve that controls air in the throttle body (IAC) I guess it's called was dirty. Lot's of carbon buildup.

That is something I already checked Robertwav1. And I'm sorry that I didn't specify year but it is an 87 sitting in a 58 chassis. The engine is pretty stock with the exception of some good roller rockers and a Chevy experimental cam.

 

[DonB]

How much vacuum is it pulling? Since you said the timing is "ON" and your vacuum hoses are good...

Considering all the other basic stuff is right;
It actually sounds like the EGR could be carbonned up and hanging open. It's NOT supposed to operate till the engine warms up, but if the pintle valve in it is carbonned up or even burned off, it will be open cold and make it run very bad. Unfortunately the EGR is in a "bear" of a spot to service.

Either google checking the EGR valve or PM me and I'll explain it. You'll need a hand vacuum pump to do so.