How's the temperature doing? Typically from experience in the past is that when the temperature starts to creep up, it starts doing that to try and circulate the water to cool the motor. Second, check for vacuum leaks. If you don't find any at first, get the motor good and warmed up until it starts loping like that. Then go and check them. It could be that the leak doesn't show itself until warmed up to a certain point.

Richard <img src="/forums/images/graemlins/patriot.gif" alt="" />

Had an 89 Isuzu Pickup
Had a 94 Mitsubishi Eclipse
84 Honda XL185S
Had an 89 Isuzu Trooper w/ 3.4 V6
01 Toyota Tundra SR5 V8 4Door Access Cab
http://community.webshots.com/user/rsayloriii