weird 86 k10 problem

[benoit454]

Ok first off some info, 86 k10 short bed, fresh rebuilt 350, stock gm intake, headers, summit cam/lifter set, stock rings and bearings setup(replacement) stock heads, brand new aftermarket edelbrock 600 cfm manual choke carb. Autolite double platnum plugs.

Well first edelbrock I had started flooding over and leaking gas out the throttle shaft, it had 90 day warranty which is total BS!!!! So bought a new one.

Thing ran fine for a couple weeks, now it's acting up.

Here's the problems, sometimes hard start after running, drove it about 5 miles, shut it off, waited for like 30 minutes, tried to refire, cracnked for more then 30 seconds and wouldn't fire, had to hold it to the floor, then it finally tried, puffed out fuel smoke badly, and died, tried again, same deal to the floor, fired, smoked, had to rev it up hard. Done fine on the way home, no problems driving it seemed. Also seems to have a dead miss in it at low throttle or idle, after about 1/3 or more maybe 1/4 throttle the miss goes away and revs smooth it seems, if you hold it there.

Now here's where it gets a little weirder, put gas in it, seemed to do fine, didn't have that happen again, still kind of rough like a miss at low throttle, but drives fine, just in the mornings on first start and rev in park it's rough, sounds like a miss or running on 6 or 7 plugs instead of 8.

Now that wasn't the weird part, it started doing it again, and just like the first time the gas hand read 1/4 tank. Put gas in, same deal, no hard start but slight miss on first start. Runs fine. Runs fine when it has hard starts, just a real PITA to start after warmed up, and when it hits it smokes, usually have to hold the gas down to start it. Doesn't act as if it runs out of gas, but once you put more in it usually or at least hasn't yet had hard starts as long as it's not on 1/4 tank!!!!!

Anybody have a clue or idea? The fuel pump is new, i think. return line is plugged off. it used to be hard to refire with the line unplugged so we plugged it off. Since then it's always started great on refires. Just developed this problem like 2 weeks after new carb, and nothing else changed. Been doing it for about a week to a week and a half.

Only thing I can think of is to readjust the mixture, set idle speed, check plugs, replace if black, check all plug wires which are new also. Maybe change out with another set. Possibly change out the distributor cap also. Recheck timing, shouldn't have changed, unless the clamp let loose and it jumped. it has been popping and backfiring every once in a while maybe once then not again for awhile.

This trucks been one problem after another I swear I think it's cursed, it's never been right. So far I've jerked out the knocking 305, which we had changed oil sending units, and tuned up, still wasn't right, cleaned carb adjusted it, changed cams, added headers, changed carbs, wires, plugs, then had to rebuild a 350 because the 305 knocked. Can't get the tv cable to adjust right, found the TCC solenoid unplugged ever since we had it, like 2 years later. had to change dashes, guages messed up, gas tank leaked, sending unit stopped working. Now I'm having a th350 built to replace the pos 700. Radiator was plugged, and leaking, changed it, heater core blew, changed it, one hose went then changed it, another went, so now it's all new hoses, and cooling system. Now this, what next. my old man is fit to be tied, he's talking about trading it off for sure. he's really pissed that nothing ever helps it. had new tires put on, lift kit, exhaust almost everything's new, and still nothing but problems.