Didn't really know where to post this and tried to search but don't have enough time to decipher all of the post. I have to get this thing in to get fixed but unsure what the problem is and if I should take it to a tried and true repair shop or back to the dealership. Any input would be appreciated.

I have a 2005 Lariat Supercrew 4x4 with the 5.4, less than 27K miles and as far as the engine mods go just a K&N Intake system and Superchips programmer. Only run 91 octane fuel and have never had an issue with it since new and the fuel filter was changed less than 5K miles ago.

Driving down the interstate yesterday at cruising speed and when you feather it for a little more it starts to miss, can really feel it in the seat of your pants. Terrible if you have the cruise control but not noticeable if just normal acceleration. On the way home I have a 3 mile uphill grade so I got on it and it missed all the way until I got out of it. It's not throwing any codes and I reset the programmer settings back to the factory settings and it's still doing it.

I am not a mechanic so any ideas are appreciated. Thanks

 

You may be running lean with that intake and no custom tune. How many miles since you changed the fuel filter?

 

Just thought of this. With the oiled filter, you may have fouled the MAF. Sure won't hurt to clean it. There are instructions in the Articles and How To section. See the index.

 

Remove the Washoobi, clean the MAF, reinstall the stock airbox and do a Gotts/DWV mod to it - and put a paper air filter in it.

 

The fuel filter was changed less than 10K miles ago. The K&N Intake system and the tuner were installed at the same time almost two years ago and I have never had an issue with either.

If the MAF is fouled, wouldn't it do it every time I attempt to accelerate ? I'll go ahead and clean it and see what happens.

 

Update on my problem. I cleaned the MAF like Bluejay stated and it took care of the miss at cruising speed but when you put your foot in it or it kicks down to pull a grade it pops and misses and this morning the check engine light flashed for a short time but is now off.

I did find out that I have an extended power train warranty so it goes to the dealership on Monday.

Got my truck back from the dealership today, they had to replace 5 spark-plugs. No reason as to why they failed but now it runs like a champ again. Unfortunately it didn't meet any of the extended warranty criteria so it came out of my pocket.