02 EX misfire codes
 

Hi all, I'm new to the forums here, but a long time reader.

I now have a problem that I can't figure out. My wife's 02 EX D17A2 is throwing 4 codes consistently. They are as follows:

P0133- A/F ratio sensor circuit, slow response
P0300- Random misfire detected
P0303- Cyl #3 misfire detected
P0304- Cyl #4 misfire detected

I've done many tests to try to find the source of the problem, but to no avail. So far I've checked compression: 180-182-175-177. Fuel pressure is a steady 50psi at the rail. I smoke tested the intake and evap systems and found no vacuum leaks. In May I replaced the plugs with NGK-PZFR6f. I also replaced the air, fuel, and cabin filters. I cleared the codes with my scanner ( Innova equus 0303), but within 48 hours the codes were back. Yesterday I replaced the coils on cyl's 3 and 4 but that didn't seem to help much. I also sea-foamed the intake and fuel systems, but I'm not sure it did much because there was very little smoke when I restarted it.

The car has 170,000 miles on it and been VERY well cared for its entire life. The previous owner even changed the brake fluid at regular intervals. It got a new timing belt at 110,000.

The car does run pretty well, but the idle is a little rougher than the two other 02 EX's I have in the driveway. (yes, we have three of them..... and to think that I'm a Ford guy....lol) It does seem that the valves make some noise, but again not any more than the other 2 cars. I suspect something in the fuel delivery system, but I'm not sure, nor do I know much about this fuel system and I know even less about the VTec system.( I also worry that the problem is in there)

Thanks for reading through this... ANY thoughts would be GREATLY appreciated!!!

Ryc

Do a valve adjustment, valves too tight will cause loss of compression and misfiring. Swap the 3 and 4 fuel injectors with 1 and 2 and see if the problem moves.

Also measure the fuel pressure.

Thank you for the replies guys,

The fuel pressure measures 50 psi at the fuel rail.

I just took the car for a 40 mile test ride (the farthest I've ever driven the car) and have some info: I was able to run the car @ WOT from 0-80 on the interstate, as the car came to normal temps it seemed to run VERY well. It was responsive, quiet, and vibration free. I have no codes yet, but the evap monitor has not reached the "ready" state, so I'm guessing It won't give codes til it does set.

A valve adjustment sounds like a great idea, but I have no info on how to adjust the Vtec valves. If you (or anyone else) could point me in a reliable direction I'll do it right away.

Thanks again:)
Ryc

Also, sometimes a bad O2 sensor can cause misfires.

wouldn't I get O2 sensor codes though?? I don't know......

p0133

I pulled the plugs earlier and took some pics. If you look at the #4 plug (far left in the multi pic) you'll see that it has MUCH more deposits on it. The individual pics are in order: 1-2-3-4. If anyone can "read" spark plugs pretty well- please let me know if you see anything I should know.

http://www2.snapfish.com/comcast2/sl...0371_95190371/

Plugs look okay to me.

A/F ratio sensor = O2 sensor

In my book P0133 reads "A/F ratio sensor circuit, slow response". Do I have the wrong info??