First off i am going to explain what is on my truck...i have a 1997 with the 4.6L V8. it is a rebuilt engine with about 13k miles on it. rebuilt tranny also. i have 38" tires on it with stock gearing.

so now the problem...when i accelerate, it sort of pulses. I dont know why it does this, is it just because of the big tires and gearing? during normal acceleration it seems fine but when i get too about half throttle all the way up to full throttle, it pulses. it does this whether i am at a stop or while im already moving. is there something in particular that i should check? I am going to clean my throttle body tomorrow because i had to clean my throttle body on my last car so i have the cleaner...could this be the problem? or maybe like the mass air flow sensor is messed up? just some ideas that have been going through my head. what do yall think it could be? thanks for any help or suggestions.

 

When was the last time you changed the fuel filter?

 

what kind of plugs were put into the engine? and wires? and was dielectric grease used?

 

Maybe your COPs?

 

97 4.6's didn't have cops - they have coil packs and plug wires.

 

that i dont know...i bought the truck and i didnt ask that question. it looks really rusty though. should i replace it?

 

i dont know that either...although i did have all the plugs out recently because of a mis fire problem and they were all fine (just one needed to be tightened down).

 

yes

if it was anything other than motorcraft denso or ngk plugs then they may need to be replaced. and only motorcraft wires work right with the modular engines

 

ok that makes sense...but would it have anything to do with the fact that i have such large tires and stock gearing? i am planning on changing these here during the christmas break...

 

not really. that would just make it take a while to get up to speed. which it also causes alot of wear. so check your drive shaft u-joints because that could cause that same symptoms.