I have a 2007 F150 with the 5/4 L. I have owned it for two weeks and it has 64k miles on it.

Over the past few days I have notice a slight buck when going up a hill at low rpm or in slower traffic were im just coasting and then ease back into the accelerator. If i give it enough gas to downshift this does not occur. So it happens when the engine is lugged down.

I have had this happen before on my old dodge and I fixed it with new spark plugs, plug wires, and cap/rotor.

Do you think it is possible that the spark plugs need replacing at 64k miles? Any other ideas?

It is not doing it enough to throw a code nor is it doing it enough to go into the dealership under the 60 day warranty that came with the truck. I can't reproduce it when i try.. it just happens every now and then.

Thanks!

 

Also the other day i had the cruise control set at 65 and needed to get out of a trucks way that did not see me and I floored it. It kind of fell on its face for a few seconds then took off. I can not get it to reproduce this either. ( It was more than just the transmission lag when it downshifts)

 

Yes, it is entirely possible it's the plugs, but could also be that the fuel filter needs changing, the MAF and throttle body need cleaning.

 

Factory plug change recommendation is 100k, but a lot of dealers are recommending 60k. So, I would do it. Be aware of the sticking and breaking issues.

 

I have the same issue with my 07 at 71,000k. To the dealer next week, still under 100k Warranty.

 

Warranty doesn't cover spark plugs. Those are considered normal maintenance items.

 

I know this but if the truck did it enough atleast I could take it in to have it diagnosed under warranty. and since I just bought the truck they may help me out.

I am gonna try cleaning MAF, throttle body, and a fuel filter first.

The truck runs great and is getting 17+ MPG so it is not showing any other signs that it needs a tune up.

 

That happened a few times before I got a programmer with custom tunes and now.....no more downshift lag.....

 

My 06 started the exact same crap at 60k. Changed the plugs and they were worn completely out. No more problem and runs like new again.

 

Wow plugs are expensive for these trucks! I have always ran the 1.99 motorcraft plugs in every Ford i have ever owned... those don't exist for these trucks haha.

 

Something else you might consider are the COPs.

I had a similar issue with my truck (a while after I had already changed the plugs for routine maintenance) where the transmission would feel like it would buck when slowing down from 50 to 45 and then accelerating. That problem escalated into bucking (which I interpreted to be the transmission not being able to decide which gear it wanted to be in) due to a misfire.

I changed my COPs this weekend and the problem seemed to have gone away. I haven't done a lot of driving yet, to confirm, but you may, or may not, have a similar issue with your truck.

good luck.

 

Yeah, and the $1.99 ones aren't platinum and won't last 60 to 100k.

 

All of our other Ford's are modified and get raced so platinums are a no-no and yearly plug changes happen anyway.