Any kind of a load put on the motor, either by moderate acceleration or an incline take off load, the truck starts bucking, pinging, and stumbles hard. This happens thruout the rpm range of each gear. Ease into the throttle and baby it thru the gears helps, but any kind of hard acceleration, either at low end of rpm range to about the shift point, it acts like the timing has advanced and pings and bucks horrible. Just put a new cat-back exhaust on, but it didn't help.

 

Have you changed your PCV valve? My Dads 302 was doing the same thing and no one could figure it out even after a couple of trips to differnt dealers. He changed the PCV and all was cured. less than a $10 part!

This topic probably belongs in the pre-1997 forum.

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97 F-250HD,PSD,reg cab,XL,4.10LS

 

My 93 due to age, and city driving had developed horrible idling and hesitation, surging. I was getting Very fustrated with it. It turned out it, that it needed the fuel injectors pressure cleaned and the throttle body scrubbed, cleaned with cleaner. Also had the butterfly valve cleaned. It makes a big difference, and I suggest any vehicle over 50k have it done.

 

Are your spark plug wires all connected?