Want to get any info from anyone who may of had issues with there 4.6 hiccuping during downshifting and coasting. I have a classic shaker hood installed, 5 speed manual trans, Roush axel back exhaust and running custom tune from Brenspeed on 87 Octane rating. The car has done it before the exhaust and tune so not sure that is from either. speeds very but today was going 60 and downshifted from 5th to 4 and tried to accelerate and it chugged 3 times and then smoothed out. I have noticed this before when coming down an offramp coasting and try to give it throttle and same thing. Anything that can be pointed to for possible cause would be very helpful!

 

Fuel pump TSB possibly?

http://cdn.lrsstatic.com/downloads/t...sb06-09-09.pdf

 

Yeah that sounds like me, its always after going 35 miles or so on the highway

 

How many miles? Have you cleaned the throttle body and MAF lately?

 

It has only 33,500 miles. I have not had either of them cleaned was wondering about the MAF sensor too

 

If its doing it after it's going steady for a period of time (cruise or a consistant speed)
and that TSB was never done....sound exactly like the fuel pump issue.


Mine did it before the fix. I could replicate it with or without a downshift.
Just coming off a steady speed or cruise, give it gas.....chug chug chug.

 

Thanks for the info, I will look a little deeper into the TSB. sounds very much like it