Mach 1 over 5500 RPM.
 

Hello:
My car latelly on 3rd and 4th gear and at over 5500 or 6000 RPM sometimes act weird, for a quick moment act like stop pulling and them start pulling again.
Can somebody experienced something similar, any help I really appreciate it.

Thanks
GE.
guilloe@hotmail.com

Any noises?

Assuming there isn't anything mechanically wrong with your mach, just about every single dyno sheet i've ever seen of a naturally aspirated mach 1 has a tiny dip/hesitation at that rpm level. Mine had the same little dip around that rpm. My tuner couldn't tune it out either. here is an example of what you might be feeling assuming your car is working properly.

Any mods? Noises?

http://www.mach1registry.org/forums/...ght=dyno+sheet

Speak for yourself, my mach doesn't have that problem. Mine is smooth up to 6700 then it starts to lose a little.

Mach 1 above 5500 RPM
 

There no noise.
The car have the usual boltons : headers,x-pipe,cat back, intake spacer,CAI,4.30, SCT X2.
The situation sometimes at the track is that the normally run over 108 MPH at the 1/4, and sometimes had fall to 103 MPH after this thing happened.
:confused:

Thanks
GE.
guilloe@hotmail.com

clutch?

I don't think the tiny tip in power at the rpm is what he describing after thinking about it, but if you look at dyno sheets on mach 1 registry you'll see the little dip I'm talking about on just about every N/A mach.

guilloe do you have a mail order tune from SCT? Again, assuming it's nothing mechanical, a dyno pull probably would reveal your problem. You might be running lean with a mail order tune if that's what you have. I custom dyno tune might be worth it, and pick up a little extra power.

+1 for the dyno
like jjtgiants said, my mach also begins to lose power once you get high into 5k, but nothing that you would feel while driving. A dyno could work wonders in a case like this.
post some pics of your mach:)

I know about the dip, it's more noticeable in other Machs. For some reason, mine feels really smooth all the way up.

+2 for Dyno pull.

Also, how long does it stop pulling? You said it starts and stops. But no one has asked about the duration of dead zone.

Mach1 above 5500 RPM
 

Hello:
Yes, the mach 1 have a mail order tune by VMP tuning.
I run it on a dyno and it does not do the weird thing.
The only thing that I notice in the data log is that the battery voltage is low under 13 volts.
12.6875 at 5400+ to 12.9375 at 6900+.
And the car AF ratio is ok under 13.0 up top.

Thanks
G.Esteves
guilloe@hotmail.com