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I have an '82 Chevy 1/2ton 4x4 with a 350, 2 barrel. When I first bought it 8 months ago it was running great, but in the last few weeks its been struggling a bit, and then went downhill sharply in last couple of days. At first it started missing/coughing at higher speeds (90kph+), then got to the point where it was sputtering and stalling when I went above 90, 80, 70... Now I can't even get it to take any throttle. I also noticed that it would cough and sputter if I was cruising on very little throttle - ie, I could accelerate with a fair bit of gas, and no problems, but it didn't like me floating on low throttle. It idles fine, but misses at higher rpms, even when its not in gear. At first I thought it must be fuel pump, because it also tended to be worse when going uphill. I replaced the fuel pump, and the distributor cap, rotor and wires, and put fresh plugs in. It sounds a lot better, but still I can hardly even get it moving before I have to put the clutch in because its dying on me. I changed the fuel filter when I first bought it, and it still looks pretty clean. Now I'm at a bit of a loss. The plugs were quite fouled when I pulled them, but they don't smell or have odd discolouration, just oil. It has fouled plugs pretty quickly since I bought it. Some of the vacuum hoses are not connected, but I don't think that is the culprit, because they haven't been connected the whole time, and my problems have only been in the last 6-8 weeks. I'm at a loss where to look next, any suggestions? I thought I would check to see if there was a second fuel filter in the lines somewhere, but that was the only thought I had.
 

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350 problems

It sounds like a cam problem. I know when a lobe goes soft it can pop threw the carb,if you have a bad exst lobe.could also be a hurt timing chain if you put a timing light on it , and the mark flots alot the chain is hurt. hope this helps. CHRIS
 

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I would try testing the module first like 67 said but I have seen a worn distributor do that too. If you put a timing light on it and the timing jumps around it could be the distributor. it could also still be a bad wire or plug. I have had brand new wires that were bad.
 

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It might be a bad egr valve that is coming open too soon. This vintage of detroit iron has some real junk engine management system with a lot of vacuum controlled delays etc. If it has the esc system that would be my guess tho. This system manages the spark for emissions. It looks just like a regular HEI distributor but has a 4 wire connector coming out from under the cap. There was supposed to be a way to unplug this connector and put a jumper wire in to bypass the system but I was never successful at making that work. What I did was just put the older style module and pickup coil in the distributor and eliminate that troublesome system. Also the wires on the pickup coil will break off inside the insulation over time. It will have contact idling but a soon as the vacuum pulls the breaker plate a little the wire looses contact. This can also cause similar problems.
And lastly, check for a plugged catalytic converter. They will idle fine but as soon as you start building rpms the back pressure builds up and will even start popping back through he carb. It can also force the egr valve off it's seat causing a lean mixture which just makes things worse.
 
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