05 Monte Carlo SS 3.8L SC - 110K Miles

I'm having a weird & inconsistent hesitation. Usually around 1500 RPM and 90% of the time going uphill. You can feel the car jerk a bit when it happens, but on a flat road it doesn't happen as much. I just had my plugs changed at 103K. I was thinking it might be the Cat building up back pressure, but not sure. I plan on replacing it anyways with a ZZP Down pipe & Cat.

I guess the jist is, what are your guys' thoughts on the issue, & if you have the ZZP Down pipe, how doesn't preform and sound?

 

This is either an ignition or transmission problem most likely. How old are the plug wires? I had the same issue and it was a bad plug wire to cylinder #4 for me. Does the transmission shift smoothly?

 

I'm with SuperchargedMonte sounds like a plug wire , are they the original set ? A few other idea's might be fuel filter, air filter and brand of plugs or perhaps you cracked the porcelain on a plug or the gap on the electrode installing them Good luck.

 

Plugs re new as stated about 7K miles ago. Trans shifts fine.

 

Wires changed with plugs 7K miles ago. Filters were changed at my 100K tune up.

I don't think it's a trans. If it were a failing trans, it would hold gear and slam hard? Gear shifts are smooth. It's just a stutter going uphill at a certain RPM, rarely happens on flat ground, which is why I'm thinking my Cat or even MAF now that I think about it.

 

Car kept randomly stalling today. Figured I'd try something simple, unplugged my MAS and problems gone. Ordering a new one.

 

Did you mean MAF? What brand did you go with?