Mine spits, sputters and back fires under a load, and doesn't want to idle as well. It also seems to be burning a little more fuel and something seems to be rattling from under my floor board when idling. I check my spark plugs and 3 were fouled. I repaced them and it does run better but not like it should. Also, I checked my MAF and it's clean as a whistle.

 

get this at like O Reilly's, NAPA,etc...and get some good carb cleaner. Take off CAI, and take off MAF and use this cleaner. Then, with the Chemtool, what I used, and get a screwdriver, open the throttle plates of the TB, and spray in there and get it good and clean. You may get a rag and wipe out any larger black suit. But clean well, leave it open to air out, spray of MAF, and reassemble after 5-10 min.

Worked perfect and fixed mine.

 

Do you have cats? I wonder if your cat converter has broken up and is rattling and plugs the exhaust outlet under load.

 

Nope no cats. I'm wandering if I could have gotten a hold of some bad gas somewhere, or it just needs a re-tune really bad. Other than that I'm thinking it's either a bad sensor or a vacum leak somewhere.