Stalling 1999 Rx300

[mennypenny]

Hello everyone... I've been worried all weeked about my car. It has started stalling at the worst times. I have a 1999 RX300 with 179,000 miles on it and I'm wondering if it's time for a new one. It has stalled 5 times. (1) Cold in the morning at a stop sign, (2) making a left upon deceleration, (3) on the free way decelerating for traffic, (4) exit ramp, (5) reversing. All of these stalls appear completly random. Somtimes my car is completely cold other times is has been running for an hour. I took it to the garage NO CODES. Upon investigation this weekend we discovered my after Cat O2 sensor had lost it's nuts and was just bouncing around in the exhaust pipe and finally just fell out.... COULD THIS BE CAUSING MY PROBLEM. I LOVE my car it has treated me so well but now I'm kinda afraid to drive it. Can anyone give me some words of encouragement?

[blk_on_blk]

To really get a good feel for what's going on, you'd have to be a little more detailed... such as how is the rest of the driving characteristics? How's the fuel economy (any noticable drop in fuel economy?)? Is the engine sluggish? So many questions.

Then, we would need to know what all kind of maintenance has been done to the vehicle. Stuff like the basis... how clean in the air filter? A REALLY dirty filter can cause sporadic stalling problems. Maybe your MAF is dirty (and if it's never been replaced or cleaned, I'm sure it is at 179K)... it's an easy remove, spray with electrical cleaner (but wear rubber gloves, for that spray is nasty), and replace. It could be your IACV... do you ever have any problems starting? Sometimes hard to idle? That could use a good cleaning, too.

Several things could be going on that cause sporadic stalling and not throw a code or a check engine light (CEL). The fact that it's upon deceleration in a couple of your instances would tell me your problem has to do with air intake; these are naturally aspriated engines and require the 'sucking' of the cylinders to pull in air... if that airway is restricted, then times when the engine is least able to suck in air (like deceleration), it could cause stalling.

So, you'll probably want to check a few things first: air filter, air duct (look for cracks), small hoses on the air intake (see if they have fallen off or are cracked/missing), check the MAF (Mass Air Flow) sensor, etc.

As to the Cat O2 sensor losing it's mounting and being loose in the exhaust, then falling out... I would think that would throw a CEL and codes, for the readings should have been way out of whack once it fell out. That could cause your stalling, but being that far back in the exhaust system, and it not showing any codes when it fell out, that's very suspicious and not likely to cause stalling.

[tmastres]

To really get a good feel for what's going on, you'd have to be a little more detailed... such as how is the rest of the driving characteristics? How's the fuel economy (any noticable drop in fuel economy?)? Is the engine sluggish? So many questions.

Then, we would need to know what all kind of maintenance has been done to the vehicle. Stuff like the basis... how clean in the air filter? A REALLY dirty filter can cause sporadic stalling problems. Maybe your MAF is dirty (and if it's never been replaced or cleaned, I'm sure it is at 179K)... it's an easy remove, spray with electrical cleaner (but wear rubber gloves, for that spray is nasty), and replace. It could be your IACV... do you ever have any problems starting? Sometimes hard to idle? That could use a good cleaning, too.

Several things could be going on that cause sporadic stalling and not throw a code or a check engine light (CEL). The fact that it's upon deceleration in a couple of your instances would tell me your problem has to do with air intake; these are naturally aspriated engines and require the 'sucking' of the cylinders to pull in air... if that airway is restricted, then times when the engine is least able to suck in air (like deceleration), it could cause stalling.

So, you'll probably want to check a few things first: air filter, air duct (look for cracks), small hoses on the air intake (see if they have fallen off or are cracked/missing), check the MAF (Mass Air Flow) sensor, etc.

As to the Cat O2 sensor losing it's mounting and being loose in the exhaust, then falling out... I would think that would throw a CEL and codes, for the readings should have been way out of whack once it fell out. That could cause your stalling, but being that far back in the exhaust system, and it not showing any codes when it fell out, that's very suspicious and not likely to cause stalling.

Everything he said. And if its not the loose 02 sensor, then search for IACV on this forum. The Idle Air Control Valve is probably one of the most common problems affecting these vehicles and , luckily one of the cheapest and easiest to repair. Not only that but the fix is extremely well documented with pics and everything. With the mileage and age of your RX this would be a great place to start.