Pulsing power when trying to drive at constant speed.

[Supercharged Vipermad]

Since it's a 97, then I don't think it's TB synchro.
You can check easilt for this. Just make sure the driver side opens very slightly before the passenger side does.
Do you have an aftermarket exhaust, or did you remove the cats? If so, then this is normal. On very light throttle, the cars do seem to pulse. Just another reason to keep the pedal down. Mine does this; started happening after I added headers and exhaust w/o cats.

 

[Steve-Indy]

Might recheck gasket...should be easily done by dealer(YOU can look yourself to see if it has sucked inward...ask dealer to confirm, replace if not right). Good luck.

 

[Robert Dyck]

mickster ....... I think these guys are on the right track. I had the exact same problem with the 97GTS. Check the intake manifold gaskets for leaks.

If the gasket is replaced, it should be retorqued after warm-up. The OEM torque sequence and procedure is important to follow. (Note that mine leaked a second time)

Also, on the retorque after warm-up, I went to 105 lb.in. versus the OEM-specified 95 lb.in. Have not had a problem since.

 

[Sean Roe]

If all else is OK, then you're probably feeling the PCM dither (cycle) the air / fuel ratio between rich and lean. You may want to try one of our engine calibrators. A nice side benefit to the performance gains is that it eliminates about 90% of what you're describing. If it doesn't help, send it back. We offer a full money back satisfaction guarantee for 30 days. Plenty of time to try it out.
See it at www.roeracingonline.com/portfolio.html

 

[Bill 96 GTS]

I haven't tried this on a Viper but I have found leaking intake gaskets by spraying carb cleaner or WD 40 around the ports. Any leak will be obvious. I'm not sure what carb cleaner will do to the Red crinkle paint so be careful. Maybe the WD 40 would be better. A little 409 or simple green probably wouldn't hurt either. I haven't tried them.