hi everyone i haven't had a problem until I hit 170k. first it threw the code for 02 sensor i replaced it with an oem bosch ran great for 2 weeks. then it threw code 43 I replaced fuel filter, plug wires, cap, rotor,vallve cover gasket-especially the plug seals, new plugs,fogged the intake and put in enough fuel injector cleaner to start a cessna. driving from stop light to stop light its fine. when i get on the highway after 15+ minutes at 75+ it starts to surge, then it throws engine light-runs better but i can still feel it missing or surging. now ive read in here about dont use bosch go denso. but if the check engine light is on and its still surging wouldnt that be something else? because once check light comes on no longer using input from o2 sensor.


Modified by 93 hoopdy at 7:54 PM 9/1/2007

 

I chased the same problem at 310k miles, did a full tune up, changed O2 sensor to no avail.
Drives rough and stumbles until CEL turns ON then it drives smooth.
Changing the ECU fixed the surging but still throwing code 43.

Chased down vacuum leaks and found the throttle body gasket cracked. Got that fixed and has never thrown the code 43 ever since.