ok... ive posted this in the "engine" part of this forum and now im gonna try here.. i have a 04 f150 5.4 3v with about 59k. i bought with 35k. i recently purchased the roush offroad dual exhaust and after i had it installed i noticed that my truck is "missing" around 3000-4500 rpms and goes away after 4500 rpms. this only happens when i mash my foot in it.. i know the exhaust didnt cause this but maybe it opened up a problem that wasnt as noticable before the install. i took the truck to a ford dealer and they hooked it up to a diag and said nothing was wrong. they installed all the updates available to the computer. i left the dealer and the truck was still having the same problem. i took it back and had the tech( who said hes been workin here for 20 some years) and i had him ride with me. and in a matter of 30 seconds he noticed the "miss" and confirmed it was a miss. he said he is 95% sure that a new set of plugs will fix this.. ive had a lot of other people say that thats bull ****. wouldnt the diag show a miss??? ive tried rebooting the computer and cleaning the MAF and still has the "miss". does anyone have any clue what can be causing this??? just wondering before i spend the money to get new plugs(which are expensive!!) thanks

 

if you dont believe him take it to another mechanic, see what they have to say. but i would just change the plugs. thats my 2 cents

good luck

 

Not too sure, but getting new plugs wouldn't hurt and may actually solve it.

 

thats what im thinkin too. i was just tryin to get some other input before i spent the money. thank you for ur time and input

 

Hope you get your "miss" corrected, but how do you like the exhaust system overall? Did you notice improved fuel economy or power? I am thinking about installing this on my 08











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