ok while driving i noticed a problem. if i punch it or floor it my lights and dash lights dim, as well as the battery gage goes down to the red i had the battery and alternator checked and they are both ok, any other ideas what the problem could be

 

Not sure about it, but it sounds like a bad contact somewhere (check ground and "+" connections from a battery to body/"+" box for corrosion, clean everything, check alt connector), or a bad voltage regulator built-in alternator. I suggest you double check this.

 

Hey man, a 98 Grand is a ZJ not a WJ

Sorry to hijack your thread 1sicv6...good luck with your car

 

[QUOTE=joed4640]Hey man, a 98 Grand is a ZJ not a WJ

My mistake Changing sig...

 

have the system checked by someone else.


also check the condition of the batery termonals.

next make sure that the belt is in good shape, the tentioner is not lose and that the water pump is not driping on the belt

 

do you have underdrive pullies?

 

no car is stock, im gonna check every connection tomorrow, belt is fine too by the way, not loose at all

 

Check and make sure the terminals are not corroded including the one form the alternator to the battery.

Also like said check the tensionor. Could be putting slack on the belt with the added power, causing alternator not to work.