Hi, my 1990 Integra sometimes stumbles just when starting off, usually under extra load (like starting on a hill). It's sort of a bap-bap-bap-bap...vrooomm (the bapping being sort of like running on two cylinders, the vroom being normal engine operation). The bapping goes away once the rpm's increase.

I have been getting a code 43 and after reading a lot of the threads here and elsewhere decided to disconnect the Co2 sensor, since that can be one source of the problem. I just took it out for a short drive and there was no bapping.

So I'm wondering does that mean the Co2 sensor is the problem, or that by disconnecting it the computer runs a closed loop, ignoring all the other sensors which could be the source of the problem, thereby fooling you into thinking the problem is the Co2 sensor?

I ask this because in a similar post the owner disconnected the Co2 sensor, the car ran better, then the problem returned when they installed the new sensor.

Thank you.

 

Im interested in knowing the answer to this as well.

 

Not much to report so far, but after driving it further the stutter is there whether the C02 sensor is connected or not. So I know it's a fuel issue and it seems to happen once the engine is fully warmed up, but that's it at the moment. I'll post when I find the solution.

 

Check plugs, wires, cap/rotor, and fuel filter. Leaving the primary o2 sensor unhooked would cause the engine to run in open loop however you did not specify which o2 was disconnected. Are there and related idle issues or only issues during accel?

 

It happens under two specific conditions (once the car is warmed up):
-just when you apply the first bit of throttle from idle, it stutters an instant and then revs
-just under 2,000 rpm under load

Code 43 indicates fuel issue.
New rotor, plugs not very old.

Thanks.

 

So from here i would check the filter and verify the fpr is working properly

 

I'll do that, thanks. I had the top off the fuel filter to check pressure, but didn't have the right adapter so will get one and check pressure as well.