Okay, so at the moment this isn't the most dire of situations concerning my car but I'd love to find out what in the name of all that's holy is going on with it since it's been so wonky lately.

Last year (2007) I bought a 1993 4cyl Camry with 91,000 miles on it. I had the front axles replaced at that point, and looking back at it's previous mechanic bills it got a new timing belt in 2002, a new coolant reservoir and hoses, and I replaced the radiator a few months ago.

About 3 months ago, after several weeks of noticing a slight sluggishness in acceleration, I was stopped at a light after driving in some hellish Floridian summer heat when my car shuddered as if it were going to stall. I got it home alright but the next couple times I went out, same problem. I'd just gotten back from a short trip, parked in the driveway and when I took it out again about 30 minutes later it stalled at the stop sign at the end of my street. I changed my spark plugs at that point and it seemed to stop. Unfortunately after a couple of days it just wouldn't start. It cranked but that's it. I sanded my distributor points and suddenly it was back in business.

Again, unfortunately, it decided to stop cranking entirely at that point. No sounds at all when I would turn the key. I took the starter out and brought it to Auto Zone where they tested it (twice) and said it was fine. So I put it back in, car still won't crank, unplugged and plugged back in the igniter wires, removed the bottom dash panels to inspect the ignition wires, still wouldn't crank, and suddenly it starts! It has started every time since then, in cold weather and hot.

I haven't driven it for more than about 45 minutes at a time, every other day, since then so I don't know whether I haven't driven it enough yet or there's another problem but after taking it out for about 30 minutes the other night it acted up again.

It was about 53 degrees out and I drove it around the neighborhood for about 30 minutes, only getting up to about 45 mph at the fastest. Everything seemed fine at stop signs and whatnot, it idles rougher now than before I started taking things apart. Eventually, I decide to come home and as usual, I sit for a while, listening to the engine. Also, I park in the flat part of the yard so I wasn't facing up hill or anything when this happened. I pushed hard on the brake for a bit to see if that would make it shudder but I got nothing so I popped it into park and waited for a bit to see what would happen. As far as I remember, I was up to normal operating temperature by then and as I listened, the rpms started to fluctuate. The engine hummed up and down and up and down and up and down... in park. With my foot off of the brake and off of the accelerator.

As far as I can tell, I need to clean out my IAC and my EGR but I don't want to take them off to do it. If perhaps someone has a different hypothesis, I'd love to hear it. I've speant several days surfing these forums and can't find exactly what is wrong.

I think you have 2 problems.

1. As far as the fluctuating idle, I would first check all vacuum lines for vacuum leaks. Make sure to check the large intake tube leading to the throttle body. They can crack and cause large leaks of unmetered air to enter the engine. If you can't find any vacuum leaks, I would agree with you that the next most likely cause would be a dirty idle air control valve. Remove that large tube leading to the throttle body and clean the throttle body paying particular attention to spraying the cleaner (throttle body cleaner or O2 safe carb cleaner) liberally in to the square or diamond shaped port at the base of the throttle body. That port leads to the idle air control valve. Spray down there first and then go on to clean the rest of the throttle body, as the cleaner soaks in the idle air control valve. Then put everything back together and start the engine. Take the car for a 10 minute ride to clear all the cleaner out of the engine. Most times this cleans the idle air control valve without removing it from the throttle body.

2. The sporadic no crank problem sounds like the common worn starter solenoid contacts problem. You can varify this the next time the car won't start. Have someone hold the key in the start position while you go under the hood with a hammer or good size wrench. Give the starter's solenoid a moderate hit. If the starter now turns, you have varified the worn starter solenoid contacts problem. Do a search on this forum for "starter contacts" and read up on the problem and it's cures.

Good luck.

Mike

Thanks for responding Mike! :) Unfortunately, I tried cleaning out the throttle body/IAC valve and as I was driving it around, it stalled out on me! I nearly creamed a mailbox. Before I'd cleaned it out, it was hesitating/surging/jerking when I would put my foot on the accelerator. Are these typical symptoms of a specific problem?

As a side note, I don't know if it's important but my tachometer has been broken since before I bought the car. Also my cabin/dome light has burnt out twice in 6 months. I didn't even replace it after the second time.

"it was hesitating/surging/jerking when I would put my foot on the accelerator. Are these typical symptoms of a specific problem?"

They can be just about anything. Are you trying to describe an actual misfire or a hesitation? Did you ever check all the vacuum lines for leaks? Have you checked for stored trouble codes? You can do that yourself with a paper clip and any manual on this OBD1 generation car. There are Toyota technical service manuals stickied at the top of this forum, that are available for free downloading. Download the generation 3 manual. Then use it to check for trouble codes. If none are found, I would check/replace the other ignition system parts; distributor cap, rotor and plug wires. You said you replaced the spark plugs and that seemed to help for a while. That's what leads me to think of other ignition system parts. New plugs take less voltage to fire than older plugs. As they get a bit older they require a bit more voltage. Perhaps your ignition system just can't deliver the proper voltage needed. Aside from that I agree with removing and cleaning the idle air control valve and the EGR valve. I would try the ignition system components first.

PS:One more thought. Check the coil inside the distributor. They can go with age and mileage and cause the kind of problems you are describing. You will need a digital volt/ohmeter and the specs from the manual to do this.

Mike

At the risk of sounding like a broken record, I would place my money on the ignition coil. Bad gas could also do it.

As Mike pointed out, the no-start problem could be any connection in the starter circuit, including the solenoid contacts and cable connections from the battery to the starter and ground.

What about the Sparkplug wires? If things got better when you added new sparkplugs but not wires and then went to hell again then it could be the wires.