'90 Camry engine stumbles

I am having a similar problem with my 91 Camry LE. I have also changed my wires, cap, rotor and plugs in the past year. Here are my questions to you: 1) Is the pattern of miss the same for all cylinders as shown by the timing light? 2) Did you make sure that the wires are not jumping its spark to any ground point in the engine?

I recently passed my emissions test after struggling with several retests. I think a partial cause of my early failures was because of a bad distributor cap. BTW, I was failing because of high hydrocarbons (usually caused by unburned fuel). I will be looking forward to your progress on this problem.

Al Kondo

The "miss" doesn't change if I move the wires around. I'm as certain as I can be, without sophisticated electronic test equipement, that they are not shorting or crossfiring. All the cylinders are missfiring and there is no pattern to it. I have a Haynes Manual for this engine and it lists many possible causes of an engine miss, including faulty emissions system components, bad/clogged injectors, and vacuum leaks. I suspect the ignition system because of my timing light tests which indicated spark drop out. I'll be sure to post my progress for those who might have this problem now or in future.

likely a bad coil

It's possible that the problem isn't in the ignition system. You may want to take a close look at the intake air boot. Any splits in the boot allows unmetered air into the engine.

Yes thank you. The h41 file should definitely help me with trouble shooting. I'm not in a hurry to get to it since the temp here has dropped to -5 (18F) and the car still runs. I will post my progress here though...

improvement.