98 camry 4 cyl i'v replaced plugs, wires, & 23 coil but still misses mostly at low speed & idle. I think it is ECU but don't know how to prove or if can be reset. My name is josh at [email protected] Thanks

Motor has to be replaced or rebuild in case you have low pressure in one of its cylinders. Is that your case?

Vacuum leak,fuel filter,battery and conection.

You can not do that

You need to have knowledge & professional
test equipment

ECU if that is correct for your vehicle, seldom fail
& then you don't fix it,they get replaced with a new
or reman one & may have to be flashed to even work

I think you need to tell us why your here, as to the vehicle
problems that brought about the question

it may be an injector problem on that cylinder, the injector could be blocked or the wiring or connector is faulty.....hope this helps......cheers.

this could be caused by an ignition problem, wrong parts, or a timing problem.
try using ngk or denso(ngk recommended) spark plugs, ngk spark plug wires, and if needed new coils. ngk and denso are the factory recommended parts for the model, i have a 98 camry lewith a 2.2.
also if it is low mileage, below 200k or doesnt leak oil, try castrol syntec 5w 30 oil and a k&n air filter

most likely fuel /demands more on higher speeds and too much at idle have seen few ecu problems however in this case i would check injectors first let me know and please rate this info

http://www.artsautomotive.com/japanese-non-hybrid/134-leaky-water-pump-causes-low-power-on-a-1995-toyota-corolla

You didn't post your engine size so please pick the applicable diagram:



1996-98 4.3L Engines Firing Order: 1-6-5-4-3-2Distributor Rotation: Clockwise



1996-98 5.0L, 5.7L and 7.4L Engines Firing Order: 1-8-4-3-6-5-7-2Distributor Rotation: Clockwise




4.3L Engines Firing order: 1-6-5-4-3-2 Distributor rotation: Clockwise



4.8L, 5.3L and 6.0L Engines Firing order: 1-8-7-2-6-5-4-3 Distributorless ignition system (one coil on each cylinder)



5.0L, 5.7L and 7.4L Engines Firing order: 1-8-4-3-6-5-7-2 Distributor rotation: Clockwise

2 airflow sensor out of operating range 3 coolant temp sensor out of operating range 4 oxy sensor indicates full rich 5 throttle potentiometer/airflow sensor... (low throttle pot signal with high airflow sensor signal) 6 throttle pot/airflow sensor...... (high throttle pot signal with low airflow sensor signal) 7 throttle pot...idle fuel adjustment failure(idle speed??) 8 intake air temp sensor...open or shorted circuit to sensor 11 Throttle pot at idle: Throttle pot idle trim out of normal range 12 Airflow meter: MAF signal out of range 14 Coolant thermistor: Resistance out of range or static during engine warm up 16 Air thermistor: Resistance out of range 17 Throttle pot: Out of range 18 Throttle pot/Airflow: Low throttle pot signal at high airflow 19 Throttle pot/Airflow: High throttle pot signal at low airflow 22 Fuel pump drive: ECU output to fuel pump relay 23 Fuel supply: Engine running too rich 24 Ignition Drive: ECU output to ignition Amp 26 Air leak: Engine running too lean 29 ECU self check 33 Injector Drive: ECU output to injectors 34 Injector: Looks for Injector dribble 37 EGR Drive: ECU output to EGR switching valve 39 EGR check sensor: EGR not working (normally pipe blocked) 44 Lambda (O2) sensor: Poor mixture control rich or weak (or misfire) 46 Idle speed Control valve: ECU output to Coil AB 47 Idle speed Control valve: ECU output to Coil CD 48 Idle Speed Control Valve: Stepper motor grossly out of position 66 Air pump: ECU output to air pump relay 68 Road speed sensor: Seen speed < 5km/h at high engine airflow 69 Drive/Neutral switch: Seen cranking in "D" or high airflow in "N" 89 Purge Valve drive: ECU output to purge valve
this is all I could find

Trying to solve same problem on my 1994 ford Taurus. So as I see it just need to rethink what we did wrong to begin with and we could have put one of the wires on wrong (in wrong placement) or bad conection.