I have a 02 Dodge 3500 HO manual trans. Just installed a new VP-44 and fass fuel system. When in cruise loaded, if I go to accelerate (cruise on) there is no throttle response and other times in cruise it will not maintain road speed if I start going up a grade. The problem is intermittent. No fault codes in ecm or ecu. No problems at all with cruise off normal driving. Its like the ecm is ignoring the throttle. Ecm has never been reflashed. Any ideas, tsb's ???