2007 hemi 5.7 sluggish engine

[25or624]

Ramheads, this GMC guy just took a big leap and bought a beautiful 07 5.7. (Yeah, it's a hemi). At very slight throttle the engine seems to hesitate and even miss a bit. A little more push on the pedal and it takes off and seems to run fine. Averaging 14-15 combined mpg. Could it be plugs, coil packs? Tx.

 

[SYKRAMMAN]

Ramheads, this GMC guy just took a big leap and bought a beautiful 07 5.7. (Yeah, it's a hemi). At very slight throttle the engine seems to hesitate and even miss a bit. A little more push on the pedal and it takes off and seems to run fine. Averaging 14-15 combined mpg. Could it be plugs, coil packs? Tx.

Welcome to the forum. How many miles are on it? Do you know any history of the truck? Is it throwing any codes? I recently bought an 06 that had a tiny stumble from takeoff, plugs fixed it.

 

[25or624]

Welcome to the forum. How many miles are on it? Do you know any history of the truck? Is it throwing any codes? I recently bought an 06 that had a tiny stumble from takeoff, plugs fixed it.

117,000.

 

[25or624]

I'm thinking plugs. A lot of you guys seem to like the Autolites.

 

[ST-8]

I'm thinking plugs. A lot of you guys seem to like the Champions.

Fixed that for you

 

[SYKRAMMAN]

Champion #RE14MC44 are the hemi heartbeat.

 

[justin13703]

The champion coppers are the best, they only have a lifetime of around 30,000 miles so chances are the previous owner wasn’t keeping up with them. It might even still have the original plugs in it. Definitely replace them first.

 

[Blackdodge2010]

Clean the MAF sensor. If it is dirty then it will cause a slight hesitation like you describe. Its pretty easy to do. All you need it a can of MAF sensor cleaner, { do not use anything else} and spray it down, let it dry really well, put it back on. Good to go.

 

[LoneWolf3574]

The champion coppers are the best, they only have a lifetime of around 30,000 miles so chances are the previous owner wasn’t keeping up with them. It might even still have the original plugs in it. Definitely replace them first.

I had between 0.052 and 0.060 gap in my plugs when I changed them out. I'm not normally a fan of Champion, but my 5.7L definitely woke up some after pulling the old Champion #RE14MC44 and putting new ones in. Just remember to put some antiseize on the threads before installing the new plugs, it helps when it comes time to replace them again.

 

[fastf]

Run a can of seafoam or Berrymans B-12 injector cleaner through a tank full you might have a injector not spraying like it suppose too.

 

[pawpaw01]

A good tune up usually helps a lot. Cleaning the throttle body would not do any harm either. Let us know how it does as you go along, welcome to the forum.