Need help with strange electric problem

[DavePont]

Hi there! I haven't posted here in a while now!

I have been having this problem with my Camry (1992 LE, 112,000 KM). Occasionally, when I slow down for a stop or a red light, my RPM go under the normal level they stay at (usually hangs around 1000 when idle or parked). They drop down to near 0 and, if I stay idle for too long, the car just turns off, and warning lights turn on in the dashboard. The car is then veeeery hard to start.

The problem gets weird because it is not constant. For example, it happens approximately once every 3 slowdowns for stop signs. Another important detail is that this used to happen all the time before, didnt do it a single time in the winter, and now it goes on again. The first time I noticed this was on a very rainy day, so my guess is it has something to do with humidity. At my local garage shop, they changed my spark plugs and (candles?) and it didn't fix the problem.

My way of fixing this is, when I slow down for a stop and notice my RPMs seem to be going too low, I go to neutral and give it a little bit of gas, to put the RPM up to 3000, then when it comes down, it stalls around 1000 like normally.

Anyway, if anyone can entice me into solutions, I haven't found anyone with a similar problem... Thank you for giving your advice/opinion!

[toyomoho]

Check IAC valve, might need cleaning. There should be a few TN posts about how to clean it.

[Mike Gerber]

I agree with toyomoho, first try cleaning the idle air control valve along with the entire throttle body. There are several threads here on how to do that, so do a search for "throttle body cleaning".

If that doesn't solve the problem, I would next check the coolant temperature sensor (Toyota calls it an ECT sensor). It may be out of range and telling the ECU (main engine computer) that the car is always cold, when it is warm. This results in a richer than normal fuel mixture, which is fine for cold running, but may flood out and stall a warm engine. This may explain why the car ran fine durning the Winter months when the aambient air temperature was much colder. To do this, you will need a digital volt/ohmeter and the specs from any manual. There is a generation 3 Toyota factory service manual stickied at the top of the General Camry Discussion Forum, that is available for free downloading. It will give you the specs and the procedure for checking the ECT sensor.

Mike

PS: What are candles?

[DavePont]

Wow, thanks for the help guys!

I haven't checked that out yet, but I sure will!

About the "candles", it's probably a bad translation from the french word we use, "bougies", to name a piece that I believe has something to do with spark plugs and pistons. My garagist changed both the spark plugs and those.

About the solution you guys both gave me, does it corroborate with the fact the problem never happened during the winter?

Thanks so far and please add any clue if you can think of anything, help is very appreciated because I am a total dummy in anything mechanical, and it seems no garagist has been able to help me so far.

[Mike Gerber]

By candles, do you mean "spark plug wires" or "leads" as they are sometimes referred to in England and Australia?

Mike