1998 Toyota Camry

Engine Mechanical problem
1998 Toyota Camry 4 cyl Front Wheel Drive Automatic 134000 miles

engine stalls when waiting for redlight. So we replaced the IAC (new one from dealer), it worked for a few days then stalls again, seemingly at random.
Then the local mechanic replaced the fuel filter and fuel pump (new) because the pressure was not up to par.

Then after a few days the engine stalls again. The symptom is always engine behaves perfectly when driving, but stall occured when the car is stopping. Usually the engine just plainly stalls, but a few times the rev will increase to 1500-2000rpm, hang at that range for 30 sec, then rpm dropped and the engine stalled.

Twice, the engine stalls when I engage the AC, but I can always restart the engine afterwards. And the AC compressor appears normal with good cold air and no abnormal noise. But after this two time stall, it did not stall again regardless how often I cycle AC on and off within the next 30 minutes.

I am puzzled.

Thanks in advance.
September 5, 2009.

Have they checked for vacuum leaks? EGR?

Hi Jacob and Nickolas: I apologize for the late reply. I some how did not see your email.
1. Vaccum appeared to be normal.
2. EGR valve appeared to be normal. But how to easily check the EGR valve?

By the way, the symptom was as follows: 1. Highway driving was no problem. Engine is smooth and powerful as a normal engine.
2. Idle appear to be normal if the engine does not stall.
3. When engine stalls, the idle rpm sometimes will shoot up to 1500-2000 rpm before dropping back and stall. But I also have observed the engine just stalls without raising rpm.
4. The engine stalls only during idle, oftentimes when the brake was applied. I thought the vaccum booster may have a leak, but it does not appear to be the case since idel was smooth most of the time. I started suspect Throttle Position Sensor (TPS).
5. I even changed the EFI relay, but did not make any difference,
6. There was NO CEL (Check Engine Light).
7. Could the fuel pressure regulator that is bad?



Sep 14, 2009.
The interesting part is the brake issue. Something is telling me there is a problem there. Have you had the booster vacuum tested to see if it will hold and maintain vacuum?

I question the fuel pressure regulator because when they go bad, usually they are bad.

I do have a handheld vaccum pump that has built-in gage. Do I just connect the pump inlet hose to the vaccum brake booster and start pumping out the air and see if vaccum holds?

Sep 14, 2009.
Sorry, it took me more than a week since I was out of town for a week. I checked the power brake vaccum booster while the engine was still warm. The vaccum booster appeared to be OK, holding steady vaccum at 15" at least. Also, engine itself has steady vaccum. I used the MityVac handheld tester to perform the above test.

Sep 22, 2009.
This is a tough one. I would tell you to check fuel pressure, but if the problem isn't present when checking, chances are it won't show up for you.

Here is a how to if you want to try:

This is the type of problem that causes mechanics to lose their hair. It could be a glitch in anything and may require us to wait until it gets worse.

OK, I will look into the fuel pressure thing since I have a fuel pressure gauge. I had my 86 BMW 528e fuel pressure regulator went south on me once. But the symptom was engine bucking, hesitation much more constantly. But for this Camry, the engine ran just like a normal engine, you could drive it on freeway for an hour and there wouldn't a problem. So I kind of suspecting the problem lied elsewhere.

Also, since the engine dies when fully warmed up, could temperature sensor played a role? I even reasoned that if the temperature sensor was bad, the engine will run really rough since the ECU will be metering wrong quantity of fuel.

Also, check engine light came on recently with P1133 (oxygen sensor?) And P0110 (air temperature sensor?). But neither would likely cause the engine to die like that.

Sep 22, 2009.
Instead trying to test the fuel pressure (when engine stalls), would it be easier to just swap the fuel pressure regulator? Since the fuel pump and filter both had been replaced, the only thing that could affect fuel pressure is the regulator.

Is the pressure regulator located at one end of the fuel rail? Is it a Bosch type similar to those used in other vehicles?

Sep 22, 2009.
Yes and yes, but I was just trying to save you money.

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