1987 Suburban TBI stalling...

[Bob Gervais]

I have a pretty annoying stalling problem on my 1987 Burb, 350 TBI.

A while back, I swapped distributors, with what I thought was the correct one. It was not, and the truck ran miserably. I put the stock one back in, and ever since it's stalled when putting it into D, or any gear for that matter.

I've checked: TPS voltage, timing, pickup coil, temp switch, EGR, MAP and EST operation. Checked for vacuum leaks. All seem normal.

I've replaced: Ignition coil, wires/plugs/cap/rotor are new within a year. All currently test/show good.

I actually had to turn up the idle so it would stay running in Park. If I keep my foot on the accelerator it will stay running in gear, but if I take it off it will stall after about 20 seconds or so.

I've checked and re-checked all connections, in case I knocked one loose doing the distributor install. Everything seems normal.

There's also no check engine light, complicating diagnosis even further.

This is really driving me insane, anyone have any suggestions?

Thanks in advance!