Check engine light at high speeds

[90silveraccord]

Hello there. I recently checked my ECU for error codes just for the hell of it and I got codes 1, 2, 3, 7, and 8, but NEVER received the check engine light signal. And I recently also passed my emmisions test without a problem, but the guy did suggested I change my cat in the near future(about 7 months ago). A few days ago I got the check engine light while driving down the freeway. The signal went away once I restarted the car and didn't come back until I hit the freeway again at about 60-75MPH. It only turns on at that rate of speed. I checked the ECU again for error codes and it poped up code 43.... Now I don't know if all those other sensors are really screwed or if its my ECU going crazy. About 4 years ago my car flooded due to heavy rain and I'm wondering if the ECU suffered permanant damage because of the water. Do you guys think I should get myself another ECU or start replacing sensors? I would greatly appreciate any suggestions. Thanks!

[brawl]

Well error code 1 and 43 are defective or faulty o2 sensors...the reason its tripping only at high speeds is because in order to test if your o2 sensor works properly, you have to keep it at an rpm higher than 2500 for around 45 secs to a min...which equals out to roughly around 60 or so mph. Try replacing your o2 sensor and pull the negative terminal off the battery. If you are still trippin serious amounts of codes, get a different ECU...i personally had one go out on me when it showed me 8 different codes at once...swapped computers, it worked fine.

[ckyskater733]

ive got one for sale if you are interested.....

but also, i would reset the codes, and then drive around a bit to see if they come back on, fix the problem it says, then reset it again. if theyre still coming on, it would most likely be the ecu.

[90silveraccord]

Thanks a lot for the replies. I'll try a few things before I change the ECU. I do have another question too. Can the Throttle position sensor screw with the car's voltage output? For example, When I have the car in park or neutral the voltage is 14.4 steady. When I put the car is drive the voltage slowly drops. It's not the alternator because I recently got a high output alt and even had it tested thoroughly. I havent been able to figure out why the voltage only drops(12.7) when i'm driving. One other weird thing is that I have to keep an electrical component on(defroster, headlights, A/C) in order to prevent voltage drop. Any one have any ideas on what might be causing this? Can the throttle position sensor screw with the car's voltage? Thanks!!