I have Y-straights, meaning its y piped (not true duals). Every time I get on the gas pedal, it will studder and do little deep pops for about 5-9 seconds then clear up and go. Any one else have this issue. I also have all stock cats. My truck is a 2007 F150 5.4 with Fx4 package if it matters.

 

I think mine is doing something similar to whay you are saying....the RPM's go way up but the truck does not seem to move. Stutters & sputters till it finally grabs ahold.

Do you get this issue too: After cruising at 50mph for a bit and let off the pedal the truck seems to stumble and fall on its face!?

The Dealership changed my plugs and boots, said the coilpacks were good....but it is still doing it even after the plug change. Now they are telling me it's a clogged cat, but those were changed 3 mo ago when I installed hi-flows.....
not throwing any codes and no CEL. could it be the o2's?

Im at a loss. going to a different dealership tomorrow to get a second opinion.

 

If it is not a mechanical issue, upgrade the midpipe to 3", will relieve some of the overly high velocity you are retaining and your Y pipe may be restrictive. Its best to use a Magnaflow Y pipe for dualing out tailpipes.

 

change your fuel filter.

 

my dad said it could be o2 or co2 sensors, I hope its not a clogged cat. And im thinking its because im not getting enough airflow out of the motor fast enough. I need to take it to the shop and see what it is. And I dont think its the fuel filter avfrog.

 

How many miles on it? Ever been changed?

 

Like, 49,500. Ill look at the bill from my last oil,air,oil filter change and see if the dude change the fuel filter.