Engine problems

[ltdan]

So here I am driving to a friends house at night in my '00 Civic Si, when I get a CEL. I think "no big deal". I've been getting them on and off since I added a B&M Fuel Pressure Riser. I get about a mile further down the road, and my engine starts to sputter some, and is acting a little strange. When I let off the gas, cruising at about 45mph, the engine decelerates quickly, and bucks up against the motor mount as if one of the mounts is loose or broken. As I continue to drive, it starts to get worse. Minor movements in the gas pedal cause it to buck up or down once whenever I accelerate or decelerate. Still feels like a broken motor mount. I get to his house and pop my hood. All of my mounts look good, and I can't rock the motor any. Sitting at idle, the car surges to about 1500 rpm's, back down to 800. This happens a few times a second. I pull the parking brake up, and try to pull forward in first gear, and then backwards in reverse. The motor barely moves at all, so I'm almost positive that it ISN'T the motor mounts. I check all of the cable connections near the throttle, IAC, and the other various sensors near the throttle body, but nothing appears out of place, disconnected, etc.. I shut it down, and go inside to let the car cool. After a couple hours, I pop my hood, and pull the backup fuse to clear the CEL (I shoulda read the code, but I believe it's coming back anyways). When I fire up the car, it appears to be running somewhat smooth, but the idle is a little high. Maybe no big deal, because it is colder out tonight than it was today, by about 15 degrees. When I pull out of the driveway, the 'bucking' problem is gone, and it drives fine. The way home it starts to surge at idle again, but no CEL yet. More info on this when it happens. Has anyone had a similar problem & solved it? Any ideas where to check?

The last thing I worked on my car, was to add a quart of oil, since I was just off the edge of the dipstick. Previous to that, I used carb cleaner, with the motor running, to clean oil from the breather tube off the throttle.

My car has 78k miles on the original B16A2 motor. Mods are AEM CAI with a bypass valve, B&M Fuel Pressure Riser, set to 38PSI at idle, with the vacuum connected (42 with the vacuum plugged). 4-2-1 headers, Ractive Superflow Cat, Greddy EVO Cat-back exhaust, O2 simulator on the post-cat O2 sensor, '94 GSR intake cam at factory timing, ignition set to factory spec with timing light, 10.5 lb Zex flywheel & Ram Stage2 clutch, 160 degree thermostat and 160 degree radiator fan switch

[ltdan]

I got the CEL back, along with the problems after a mere 10 miles of driving. It flashes one long and 4 short pulses with the jumper installed in the test plug. My Haynes manual reports it as an IAC valve system fault. I checked the plugs, hoses, connectors, etc. and don't see any problems yet.

[civicexstacy]

Ok, I'm having a helluva time finding an O2 sensor bypass for my 2K Civic EX. I'm about 9 days away from inspection and absolutely need this bypass so I can use my race cat. I would greatly appreciate any direction you can point me.
Thanx,
Josh

[ltdan]

Trying to troubleshoot it further, I spent 2 hours adjusting the idle-stop screw & IAC bypass. Since I did that, I haven't had any more permanent CEL's. Twice I got a rich/lean code, but it disappears after 50 miles..

I've turned my FP from 42 up to 46PSI, and gained a small amount of power. a good 1500 miles of that and no problems either.

Daniel