I'm just curious what it could be
probably no big deal...(this is in the Integra, BTW)...
It's more of a power draw, then surge.
At highway speeds (60 mph for the sake of discussion), something is cycling on and off that acts like a really weakened version of an A/C compressor kicking-on.
At constant throttle, FE drops very slightly, speed drops, and the feel of a faint "nudge" occurs -- I'm talking hardly noticeable. Then after 30 seconds, another slight bump, the power returns, FE increases and things are back to normal -- that is until it happens maybe 2 minutes later. It happens up hills, down hills -- usually at highway speeds during full TC lockup. No CEL, and the car otherwise operates the same as it always has...
It started about 3 weeks ago. Around the same time as a radiator-block installation. This may have no connection between the 2.
Theories: Since I have no idea, I'll throw out some guesses. Is it the thermostat opening and closing, causing more of a coolant pump load? I don't hear it, but would it be the electrical load of a cooling fan translating back to the alternator->belt->onward? Changes in pressure in the auto-trans / slippage? (let it not be that one...) And yes, the A/C is off
Thanks guys...
RH77