Engine stutter

My 2004 Crew Cab automatic has a bad stutter between 1500 and 2000 rpm, worse with a load on it. Once above 2000 rpm all is well again unless I have a lot of weight in it or am towing, then it continues to just above 2500 rpm. Doesn't cut out completely, and it's very uneven, not a consistant stumble. I'm thinking of replacing the plugs, then testing the coils, the fuel filter is new, it could be the airflow sensor...any suggestions?

Thanks!

Lance

 

No, and from reading some other threads it's not the best, the stock filter is. Correct me if I'm wrong.

Lance

 

No tinkering other than adding trailer brake controller....I'll check that out by disconnecting the wires one by one...

Lance

 

is the tailpipe sooty?

 

Very....

 

Found and fixed the problem!

Got new plugs and plug wires, when I pulled the plugs the center driver's side plug wasn't even snug, and the plug behind it was barely snug. With the new plugs and wires installed no more misfire!

I bought this truck about 10k miles ago (now has 80k miles on it) at CarMax, seems their mechanics aren't any better than anywhere else's.

Lance

 

plugs, wires my brother. you check those coil packs but dont think thats your issue. when was the last time you did a service to the throttle body? cleaned the fuel injectors,