Great Question! I have the same problem with my 1979 LUV 4x4 with 98,000 miles. Manual gearbox. Truck runs great, with perfect idle, after a COLD start. But when turning off the engine, say, while visiting a store, and then warm starting the engine, it start acting up as you are describing - sputtering, and will not idle - as if one would turn off the ignition key. It will however start-up again but with the same poor running problem. If you leave the truck sitting overnight (or after engine cooled off), it will start and run perfectly again until you do another warm start. I have replaced: the complete Distributor unit, sparkplugs and its wire harness, ignition coil; checked all vacuum hoses, choke remaining fully open after warm-up, checked that fuel level in the carb bowl slightly above the marker dot on the glass, checked valve adjustment. Have NOT replaced the ballast resistor but it measures around 1,3 Ohm. Identical resistor (enclosed in a metal box) hard to find. I had the stock DCH-340 carburetor checked by a 'carburetor repair guy' and he could not see any obvious problem with it! (but we did not remove the Carb from the engine however).
Could a sticking EGR valve cause this problem?? I have, however, disconnected all the hoses controlling the EGR valve, but with No improvement! Could an electric (maybe intermittent) fault cause the engine to misfire after warm start-up? If so, why is then the engine running perfectly OK after a cold start!!
I "think" I have noticed that the ballast resistor is not as warm (hot) to the touch when the engine is running normal versus when it is acting up.
Anyone with some Good suggestions? Thanks.
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