Ghost in the Machine

[rampage]

OK, pulling my hair out on 1987 Chevy 350 TBI (V20)
I've checked or replaced: Fuel pump, bypassed dual tank switch, fuel filter, rebuilt TBI including pressure regulator, new temp sensor, O2 sensor, IAC valve, EGR Valve, vacuum hoses, plugs, plug wires, cap and rotor, coil, vacuum hoses...
I had this truck running fine after I discovered the old EGR valve was actually broken right off, and it was 'free floating'. Replaced EGR and then it ran fine for a little while, but then started acting up.
Current symptoms:
Runs 'OK', (but not great, you have to keep giving it gas) when it's cold, but then as soon as it starts to warm up then it won't start at all.
It seems like the timing mark is way off. Either the distributor is off a tooth or someone swapped an old style harmonic balancer where the mark is at the top instead of 30 degrees from top.
Spray pattern looks good, I don't think it's a fuel issue.

But here's what's really weird: When I get it running halfway good, and then go to put the air filter back on (with it running), all of a sudden it starts to high-idle. It's almost like there's a short somewhere, but what would cause it to high idle when I put the air filter housing on? Only things I could think of it would touch are injector wires, EGR control wires... maybe coil wires? Then, after this high idle, that's when it quits and won't start at all for a while.

I'm really stuck here, any help would be greatly appreciated. I've never had this much trouble getting a 350 to run right... Read a bunch of threads here, I'm thinking I may need a whole new distributor. There is a small oil leak from somewhere back of block, but I can't isolate it...

 

[89Suburban]

You don't have that di-electric grease crap on the spark plug wire boot ends do you? I had that stuff on a set of wires I picked up from Autozone and they were shorting the spark out.

The injector wiring coming into the air cleaner base are known to get pinched and scuffed open sometimes.

When you set the timing the engine is warm and low idle and the connector on the brown wire on the firewall is disconnected right?

 

[74propu]

in 1991 I worked for a school bus comp in Kansas city and we ran about 600 buses and I learned 1 thing very fast if the bus would start cold but had to pump the gas to keep it running till I could get it in the shop and if it died after it wormed a little and wouldn't start till it cooled off . start with the distributor 9 out of 10 times it had a crack in the coil and would short out and fire 2 or 3 plugs at the same time and would open when it heated up so I would start there here is a good one for the money http://www.ebay.com/itm/271674951328?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

 

[smoothandlow84]

Im guessing the rotor or cap is shorting out or bad plug wires/connection at rotor. Have you replaced the plugs, wires and gapped them properly?

 

[87ChevyR10]

I would say something is up with the coil or pick-up coil. It sounds as if one or the other is breaking a connection once warmed up.

I had the pick-up coil die and the truck wouldn't run, period. I replaced all the external stuff + cap and rotor. That's when I was able to narrow it down top the pick up coil.

IF you haven't already, I'd go thru and replace all the plugs, wires, external coil, the cap and rotor and the ignition control module. If those don't fix it, then I'm afraid your pick up coil is shot.