Catalytic Converter

I'll try to summarize the thinking here:

1. You said that your car has 230K miles and suffers from poor powertrain responsiveness. The check engine light comes on from time to time and you've been told that the catalytic converter needs to be replaced. I assume that the catalytic converter DTC, P0420, was logged. (Please check the repair invoice that documents this diagnosis, to confirm whether this DTC is listed.)

2. When you notice lack of engine performance, the first question to ask is whether the engine needs to be tuned-up. Who knows whether the prior owner kept up with the 100K and 120K mile services which should have been performed 2x by now. Therefore I suggest that you replace the iridium spark plugs, engine air filter, and the air/fuel ratio sensor; and clean the mass air flow sensor, throttle body interior and throttle plate.

3. If you find that the engine performance is improved after this tune up, you may also find that the catalytic converter DTC will no longer be logged. If the engine is performing more efficiently then there's less unburnt hydrocarbon gases in the exhaust for the catalytic converter to deal with. Therefore, even though the catalytic converter is marginal, it may be "good enough" if the engine is running better.

4. After you've restored engine performance and have taken care of the catalytic converter issue, then you can focus on other maintenance like 5K mile engine oil and oil filter changes, replacing the engine coolant and transaxle ATF fluid, replacing the PCV valve and serpentine drive belt, inspecting the engine coolant pump for leaks and replacing if needed, checking the suspension and brakes, etc. There is a good chance that the front struts and rear shocks are bad, and the front brake pads and rotors and rear brake shoes probably have to be replaced. Also check with your Toyota dealer for service campaigns that are outstanding on your car. For example you can get a replacement inverter coolant pump (and inverter coolant) free of charge under a limited service campaign currently underway.

5. You'll have to spend quite a lot of money on the suggested maintenance in #2 and #4, but if you can take advantage of free labor then you're still much better off than if you go to the dealer. Considering that your car has logged so many miles, this maintenance needs to be done if you want to drive a reliable vehicle.

I hope this recap helps.

 

Take a look at the six-page summary to see the last time the spark plugs, air filter etc were serviced. You might be able to take some of my suggested items off the list if this work was done recently.

The fact that the check engine light goes off and on indicates that the catalytic converter is marginal (but not totally dead). If the air/fuel ratio sensor is replaced, that might improve your engine's performance and keep the CEL light off for a while.

You will probably not be able to get the iridium spark plugs at your typical discount auto parts store as these are special. I recommend you consult with your BF to decide what work he can do for you, then order everything you need at Champion Toyota, Houston: toyotaworld.com

They offer ~25% discount from MSRP for web orders and the ground shipping time to your Louisiana location should be very fast. Good luck.

 

Melissa Anne, I think the first step to repairing your car is to unplug the Xbox.

 

Haha, was thinking the same thing. We must be "old school", like her dad, because taking care of my lady's needs, comes before video entertainment.

 

You can always with hold _ _ _.

 

As a working man, I appreciate the days your boyfriend endures. As a mechanic, I also know how important it is to maintain your vehicle. Patrick Wong is correct with his recommendations. So with caution I make this suggestion, and appologize ahead of time if I speak out of place.

Have Toyota give you a full estimate of the work needed on paper. All of it. In your own way sumit this to your boyfriend. His being a pipefitter means he can turn a wrench. You might be suprised how dollar figures and a good woman can motivate even the most fatigued man.

 

I would caution you about using Autolite plugs or any other than the correct NGK or Denso iridium spark plugs as specified in your owner's manual, as the service life will be shorter. You might try an auto parts store that specializes in import auto parts, to see if they sell the correct plugs.

Also, if your BF is not successful in repairing your car to your liking, and you go back to the Toyota dealer for help, one of the first things the dealer tech will do is to identify and replace any non-Toyota parts that are potentially relevant to the problem. The spark plugs fit into that category. Hence, you'll get to pay for those parts 2x which is not a cost-effective move.

It's OK that your repair will be performed one thing at a time. It sounds like your BF is logging many hours - good for him, and that beats the potential alternative of being unemployed by a considerable amount. If he gets more relaxation out of playing with the Xbox than working on your car, I can't fault that.

 

Melissa Another option for spark plugs is the NGK (4996) IFR5T11 Laser Iridium Spark Plug. Amazon.com sells them for $7.73 a piece. I believe these are OEM quality [ame="http://www.amazon.com/NGK-IFR5T11-Laser-Iridium-Spark/dp/B001B0Z0B2/ref=wl_it_dp_o?ie=UTF8&coliid=I3LXNQ97PL9L2H&colid=4M9TQ7QWA7JA"]Amazon.com: NGK (4996) IFR5T11 Laser Iridium Spark Plug, Pack of 1: Automotive[/ame]

 

The original equipment plugs are either NGK IFR5A11 or Denso SK16R11.

The following datasheet confirms that NGK IFR5T11 is a suitable replacement:
http://www.ngkntk.co.uk/working/FileLib/1010%20IFR5T11%20Spark%20Plug.pdf

 

You will need to buy 8 of these spark plugs. Four you keep and four you can ship to me as a finders fee . Or you buy 4 and tell me to stuff it.

 

I prefer Toyota air filters, although you'll get all sorts of advice about what to buy. If you haven't changed your cabin filter change that one as well.