Today we installed Hooker long tube headers, O2 simms, 1.8 RR's, lid, FRA, and a tuner thing like a hypertech but different name. Might've been Diablo Predator. Anywho, took it down the road, run up the RPM's, go to the next gear and it boggs for a sec then picks right back up and takes off again?!??

Imagine speed shifting from first...... as soon as I hit second it really lost almost all of its power for a couple seconds. Same in third and fourth. Just a momentary loss in power. The engine doesn't quit pulling, it just flat out looses its hard charge for a second then picks right back up. Sorta hard to describe I suppose. Maybe the valve adjustment is a little tight?!?

The car is an M6 car with listed mods and catback exhaust and 3.73 gears.

The thig is damn stout going up through the the revs but grab the next gear and it just stumbles in power for a sec or 2 then BAM! it takes right back off pulling just as hard as before.

Any suggestions? What would you try first?

 

could it be a slipping clutch?

my first thought is something wrong with the thing you used to tune it. most of what i've hard for those hand tuners are that they start negatively affecting hp on a car that is modified more.

they work decent for a near stock car, but start adding some bigger mods (headers, rockers etc) and the tune that they come with is no longer even close to ideal.

and if you have a programmer why doo you need o2 sims?

 

Thats what the boy bought and wanted us to put on it. It was a Diablo Predator, BTW.

It isn't the clutch.

The O2 simms are for no cats whatsoever. I don't think programmers like that can disable rear O2's. I may be wrong though.

 

The Predator can with a custom tune from your dealer. Some will offer the first custom tune for free.