ArtyPA

Hi,

We have a 2007 RX350 AWD with 224,000 miles. We have owned it since 39,000 miles and it has been good to us. It has an issue that I have not been able to figure out. It has begun stalling intermittently when idling.I mean very intermittently (like once every 50 times) It has never done it when in drive only when sitting in park. More of a problem though is that it also seems to hesitate slightly on initial acceleration. It only does it on the initial acceleration, once you are in to the accelerator it seems to accelerate as it always has. it just a little disconcerting when you pull out into traffic. I fear is going to get worse. I changed the plugs at 210,000 and the air filter was changed at 200,000. It is not throwing any codes. Does anyone have any ideas?

Thanks,

Arty

john341

Check the Fuel Pump and Pressure on the fuel lines. Also clean the intake and see if the MAF sensor is in good condition. Have you changed the coils(Buy the Denso or original manufacturer one) for the spark-plug?

ArtyPA

I had one coil go bad right after I did the plugs last time and I replaced it with a Denso. The rest are original. The MAF sensor and the intake sound like good places to begin. I will have to figure out how to test the fuel pump. Thanks.

OG Member

iTrader: (1)

There is a probability that one of your "Ignition Coil Connectors" could be coming/is loose.

Reason being you mentioned a coil and spark plug replacement and the 'connectors' are quite brittle after time and tend to break. Keep in mind that these 'connectors' plug into the coil, and if broken, could vibrate apart and create a hesitation/misfire.

ukrkoz

my bet is on idle speed valve. Intermittent - as in very - possible fuel supply issue like this is pretty much impossible to diagnose. You have to hit it right when it happens.
You cab connect Torque app to your car and run long term fuel trims. Or, a scanner capable of running and recording same data live.
Personally, I pour two cans of Seafoam into the gas tank and get her out on FWY for an hour. To blow fuel supply system clean.

ukrkoz

oh, and even 4 cyl will run - poorly - with one cylinder disabled. Least to say - a V6. Plus it presents itself differently - engine sounds like it's "skipping" one cycle, with according jerk and hesitation.

ArtyPA

Thanks for the help guys. If an ignition coil connector is loose would that throw a code for a cylinder misfire? I have never put much stock in the fuel additives but I suppose the seafoam might be worth a shot.

exaktoh

matts6887

The fuel additives/cleaners can be a alternative to full on fuel system cleaning but are only temporary as u dont get as much long term or as much thorough cleaning power as u would doing a full on system cleaning via s shop.

matts6887

also one person mentioned the maf sensor. That does need to be cleaned every so often to keep your mpg from dropping too badly and yes a dirty maf can cause issues. But it is very easy to clean that. U just need to get a maf approved cleaner from any auto parts place; unscrew the maf which sits on the intake tube right near the air filter box. unscrew it, unplug the sensor plug and pull it out; douse it with cleaner, let it thoroughly dry and put it all back together and u should be good.

numbafree

If you have a code reader that reads pending codes, I would start there.

I had the same issue on my rav4, I would clean the MAF and the throttle body, if you don't have any pending codes to point you in the right direction.

matts6887

speaking of throttle body(dont mean to get off topic here) what is the best and easiest way to clean the throttle body without having to go to the expense of having a shop do it. I dont know if it was ever done on my current rx350 and i figured I would ask now as I have to go to a auto parts place today anyways to get a new engine air filter today so while im there I figured i would try and get whatever is necessary to clean it to get the max performance and fuel mileage out of mine.