I've been fighting this issue recently. The car feels normal at lower rpm, but once I get into VTEC the car heavily bogs and barely accelerates. This problem was originally intermittent, some times it would pull fine to red line and other times it wouldn't. I was running on a banked oval track the first time this occurred, so I thought it was fuel starvation, I completely topped the tank off and still had this issue. The problem is now continuous.

There is an audible pitch change and it does feel like VTEC is engaging on the larger cam, but the pitch is much different (weaker? can't describe it) then when it runs strong.

Here is what I've tried so far:
- Added fuel at the track to test for fuel starvation.
- Verified oil level at the track to test for oil starvation to the VTEC solenoid.
- Performed a MAP whack / ultimately replaced MAP. The symptoms were still intermittent but better, so I replaced the MAP with an new OEM part.
- I tried removing my VAFC and the symptoms remained.
- Pulled VTEC solenoid off to inspect strainer. The strainer looked great and I shot some brake cleaner on it just to make sure.
- Verified I'm getting voltage to the solenoid at the engagement point.
- The OEM O2 sensor shows it goes pig rich at VTEC engagement all the way to redline. While not a wideband, the OEM O2 sensor still appears to cycle normal at lower RPM so I feel the information is somewhat useful.

I haven't pulled the fuel pump out yet to look if the sock is gunked up. If I'm truly going rich in VTEC then I doubt that's the issue.

I've heard about rocker arm seal (?) issues bleeding pressure off so that the engagement pins don't have enough pressure to lock the secondary rocker arms into place. I don't have the tools called out in the factory service manual to test for that. I tried putting air pressure on the port for the VTEC solenoid pressure switch, then manually engaging the solenoid. I could not get ANY rocker arms to engage with this method, but the method does vary from the factory service manual.

Any ideas?

MY00 with ~75k. It's STR preped, so I/H/HFC/E/VAFC

 

Bueller?

 

Your up to temp right?.

Utah

 

Correct. I'm above 180°F when I'm driving, when I tested the solenoid, and the engine was warm when I tried to test the rocker arms. I confirmed temperature on an OBD scanner.

Also, I have no codes.