1994 Camry 2.2 engine stumbles and barely runs

[LagunaSeca]

I am firmly in Camry Hell. The radiator cracked and let the steam out, the car got hot. never seized and would always turn over on the starter. Compression is 200-205 in 3 cylinders, 170-175 in #2. It runs but stumbles badly when under load, although it seems to rev freely. I have replaced both O2 sensors, the water temperature sensor up by the head, the fuel filter, the air filter, the radiator, removed the idle control switch, while cleaning the throttle body, put that back on once cleaned. Also checked the DC voltage at the throttle sensor, which gave smoothly graduating readings from .9 up through about 3.55 and back. I've pulled and reset the 15amp fuse for the EFI a number of times... it runs better but still stumbles badly. No water in the oil, and no metal in the oil. I'm running out of ideas and am hoping it isn't the brains for the EFI. Any ideas? I'm just about out of them at this point. 2.2 liter 4 cylinder Camry w the automatic trans. It has 209K miles, I am the original owner. It does not burn oil. I checked all 4 plug wires first with the timing light to see that they were firing, then pulled them and set them on the exhaust shield to physically see that they all fired as the motor was turning over. My compression test was done repeatedly with no spark plugs in any of the cylinders (spinning free). The ignition timing is in the ballpark, maybe off by a degree, never been a problem in the past. The exhaust is not plugged you can feel the pulses coming out the exhaust in back. Thanks, thought I'd provide all the info I could.

[Mike Gerber]

You may be overcomplicating the issue. Missing under load is most commonly (but not always) caused by faulty ignition system components. I know you said you checked the spark plug wires and saw spark, but that test does not simulate a car under load while accelerating. Coolant spraying out all over the engine can compromise older spark plug wires and also find cracks in the distributor cap. I would replace the spark plug wires with a new good set, along with replacing the distributor cap and rotor. I would use genuine Toyota parts for the cap and rotor. Another ignition system component to check is the coil inside the distributor. As these coils age they can develop hairline cracks in the plastic. These cracks can surface when things get wet or damp, like having coolant sprayed all over the engine. Remove the coil from inside the distributor and check it carefully for cracks. Replace the coil if you see anything suspect. An aftermarket coil can be used to save some money.

Mike

[LagunaSeca]

Thanks. Today I cleaned the EGR valve and the PCV valve. Now it is running surprisingly smooth for a car without any power under load. The plug wires and rotor/cap are only maybe 10,000 miles down the road, I took the cap off and looked today and it all looked good inside, but as you say, looks can be deceiving. Will try that next. Thank you.

[Mike Gerber]

Just an FYI to add. I have seen cheap spark plug wires last as little as 1 year or as little as 10,000 miles.

Mike

[Brian R.]

NGK plug wires and other ignition components are top notch. Other brands may not last long...

[LagunaSeca]

Tomorrow is distributor day. I'm just going to pull the thing and clean in up for close inspection. I hear about some radio interference capacitor that can fail and really muck things up, most just cut the lead to it and leave it in place DOA. I hear the majority of non-Toyota distributors being sold are marginal at best, so hoping to stay with the factory item if the wear isn't crazy.

[LagunaSeca]

Thank you to everybody. One thing at a time, and this morning I started with the NGK spark plug wires, which at NAPA were cheaper than many other off-market brands elsewhere. Voila, runs like a champ. Far better than anytime recently that I can remember (bought new). Denso O2 sensors (both), cleaned PCV and EGR valves, replaced a couple of sketchy looking vacuum lines, new radiator (free under Napa warranty, it was less than 3 years, barely), and a new water temp sensor (Echlin premium). About 280 dollars and I'm back on the road with a great running car. Thanks again for all the great advice.