engine/exhaust rumble on decelleration
I am a recent 2nd owner of a 1999 F150 Lariat 5.4 w/towing package. 97k.odm
My symptom is this. Cruising at 70 on the highway and I let off the gas and coast to say 55. Over the road noise I hear a distinct exhaust rumble. If you say 'rumble' 5 times as fast as you can you got the sound. I do hear it at slower speds during decelleration but it is harder to pick out. At first it did not bug me but now I am picking it out more and trying different things. When I just touch the gas, (open the throttle butterfly a little) it goes away. I also notice on the highway that I even feel the rumble thru the drivetrain. For instance instead of a smooth coast I get a very slight hesitation surging during slow down. The rough coast is prompting me to post. (poetry in motion
From past (older) V-8's I've owned, I know this is common but have seen this go away with feedback carbs, Throttle body injection, and especially Port injection. I'm curious if others expierence this with their 5.4 and what they have done or have heard.
Thanks in advance to all,
Brendan
I know that after coasting for a few seconds, the converter unlocks and helps slow the truck. This may be the drag that you are feeling.


