I have an 87 350 TPI.
The car has no problem starting up, but it then stalls out almost immediately.
I put the engine in the car several weeks ago, so I don't know how it ran before, but for the first few days after I installed the engine it seemed to run fine.
I had it out for a test drive and the in-line fuel pump died. I replaced it and now the car starts, then slowly stalls. It seems almost as though the ECM is retarding the engine to the point that it turns off.
While it is getting ready to stall the engine begins to make a banging sound from the left side of the engine, and at times it sounds almost like a metallic clanking.
The only mods that I have made are Edelbrock TES headers and an MSD 6AL ignition.
The car doesn't backfire and the exhaust looks normal.
I have hooked the timing light up to each wire and they are all getting spark, even when the engine is dying.
I have run every test that I can find on any of the tech boards.
The ECM is giving codes 34, 42, and 54.
Please help

 

MY 88 L98 is doing the same thing maybe. Been chasing this for a couple months, haven't solved it yet. Actually seems to be pretty common in these for some reason. Everything checks out fine in my car, just doesn't start right. Gives me something to tinker with but I am starting to get irritated with it. Hope you figure it out, post if you do.

 

I ground the diagnostic and then unplugged the IAC as if I was adjusting the minimum idle air and the car now idles, but seems to have an occassional knock that causes it to almost stall out. The Idle then takes about a minute to work its way up to normal.
Also, once it is idling and I put it in gear it drops to about 300 RPM and starts to shake like mad.
When I push the accelerator the RPMs go up after a pause.
I would greately appreciate the help if anyone knows what is up.