2004 5.4L Hesitation on take off
I have a 2004 F150 Lariat 4wd with the 5.4L that occasionally hesitates on take off. It usually only does it on cold mornings or when I'm pulling a trailer. If I stop at a stop sign or get in for the first take off I can hit the gas, engine revs but the truck doesn't move, and then it kind of jerks me forward. It worries me sometimes when I'm trying to pull out intro traffic. I have 116,000 miles on my truck. It started this about 3 years ago when I was around 70,000 miles. I have never had an engine light or anything come on. When it first started I took it in for an oil change and the dealer (without knowing of my problem) said I needed a new mass airflow sensor. I took it to my local trusted mechanic who said he could just clean it so he did. I had it start happening again on me this past fall so I took it to him again. He drove it around and of course it never happened for him as it was a warm day and the truck had already been ran, plus no trailer. Any ideas what is going on here? My only non stock items are a drop in K&N filter and I have the muffler removed with a 24" echo tip welded in place under the bed. I had both items for a year or so before I noticed this issue.