1998 Toyota Camry



October, 6, 2010 AT 2:33 PM

Engine Performance problem
1998 Toyota Camry 4 cyl Front Wheel Drive Automatic 158k miles


I have a Camry that has developed an intermittent power loss. Sometimes the car just hesitates and sometimes it loses power completely. There is a code in the computer for a downstream O2 sensor heater circuit and nothing else. Is it possible that this could be the problem? I wouldn't think so, but you never know. A lot of work has been done to the car recently to include:

- new fuel pump/hanger assy (from the junkyard)
- complete new exhaust system to include both cats

It also needs a valve cover gasket and a complete tune up. Is it possible these could be the source of the problem without it throwing a code?



3 Answers



October, 6, 2010 AT 2:57 PM

Hi hamburgler1201, Welcome to 2carpros and TY for the donation

Try giving it a tune-up and see what happens, don't work the following below will cause the hesistation

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note: If it doesn't apply disregard it



October, 7, 2010 AT 7:03 AM

I've read your question correctly and understood it however you failed to check it and comeback with results so I can further assist you-Remember I'm not with your vehicle, its a lot tougher to deal with, I'm not a magicman-Good Luck



October, 8, 2010 AT 9:19 AM

Downstream sensor measures CAT effeciency, up stream sensors measure air/fuel ratio.

CAT turns combustion gasses into carbon dioxide and H2O.

The sensor could be bad, could also be a partially clogged CAT.

If you can, have a backpressure test performed on convertors, if clogged or partially clogged then CAT is bad. You could also remove convertors and visually inspect for melted material or cracks.

The heater code simply means the heated sensor is not coming up to temp in time. O2 sensors must be at 600 degrees F to operate, which is why most have heaters in them, to bring sensor to temp quickly.

I would certainly do a tune up, after which, erase code and see if car runs better.

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