Hi guys,I'm hoping that another set of eyes can point out what I'm missing to solve my problem.
I have a 1989 4.3 tbi. A little while back

A little while back i replaced my distributer in a 1989 4.3 tbi. Now I can't get it to idle at all without the gas pedal if it cranks at all. At first i just thought it was the timing. I have set and reset the timing on it several times and have no change. Usually on the first try it will start up but immediately choke out. I had a mechanic come tryto set it and got the same result. Now I will admit I'm more of a parts changer than a mechanic but I have swapped distributors in that truck several times and never had a issue. So now I have moved on from the timing but can't put my finger on the culprit. I've traced vacuum lines and eliminated the chance of it being fuel related as well. I've dumped gas and carb cleaner down the intake and it won't start consistently if at all. It will backfire at times,but not often. I changed plugs over the weekend and 3 or 4 were black and wet,which makes me beleive that I'm either getting to much gas or not enough fire. I'm hoping someone can point me in the right direction with this. It's clearly something simple that I'm missing but I can't see it.

Just as a guide I've replaced the distributor and components with new plugs and wires. I've retraced wires to make sure they are in correct firing order. I've checked injector pulse and spray,checked fuel pump,tried starting with gas in the tbi,traced vacuum lines and wires. I also used a spark checker to make sure I'm getting fire at the coil and from the coil to #1 plug. I haven't ruled out the coil yet

 

You say you checked the timing can you elaborate?

Have you checked that the marks on the crank for 0-degrees agree with #1 cylinder at TDC?
Have you checked that the distributor is installed correctly so that the rotor points to cylinder #1 connector when it is as TDC? I had trouble getting my distributor back in because it was off by one tooth on the cam gear and because the oil pump shaft rotated just enough that the distributor would not go in any other way.

I've heard of 2nd gen motors that have a crank position sensor getting messed up and having to "re-learn" but that is all I know about that. It might or might not apply to you.

 

Sounds like firing order. Is this a 2.8 or a 4.3? Different firing order. Both engines used in 1989.

Compression check will tell some things as well.