I have a 240z with a l28 motor it runs strong when it is cold and when it warms up it will cruise along the bam like you hit a wall will cut out. I thought it might be in the coil or distributer but am not sure. I also thought it could be vapor lock, but have never had any experiance with it. The car is new to me and came with this problem and for more history on it it has a new electric fuel pump and a Carter AFB carburator. Any input is appreiciated

thanks

Paul

On my '73 240 there was a known problem with vapor lock. I first noticed it in hot weather. At a stop sign I naturally would try to quick start and it would buck like a bronco. If I would take off normal speed it would be okay. Datsun offered a "fix" which was placing foil wrapped insulation around the fuel lines. With the original Su carbs the float bowls were too close to the manifold and the fuel would boil causing the vapor lock. The "fix" worked somewhat. Anyway, this was my experience. Not sure if the carter would have the same problem. Just so you know, some '73's (not sure if this is what you have) had an electric fuel pump back by the fuel tank as well as the manual up front. I had a heck of a time figuring out why it would quit running then run again then quit. Finally found out about the "other" pump and replaced the filter back there. Good luck.

I can't say about the carter carb but,the stock 240 vapor lock occured when the car sat running on hot days.Summer traffic jams were the worst! When your moving the air flow prevents it.Since your car likes cold hates hot. I would make sure your choke is turning off and your air filter is correct/clean as lack of air thru the filter acts as a choke.You could have enough rust and junk in your fuel line that the sediment collects and starves your engine.When you shut it off the debris falls back down.Check your filters.Have fun! Daniel

If you are running the 280 electronic ignition it is possible it is the ignition control unit in the distributor, I had a 200SX that did the same thing, when it was cold it ran fine, then it just quit until it had cooled down. It was the ICU in the distributor, and they are not cheap, that is why a lot of people converted over to the GM HEI unit. Just another thought....Since you say you have an L28 in it you might check to see if it still has the electronic distributor in it as well.