2005 Toyota Tacoma SR5 PreRunner Engine light

Engine light came on about two weeks ago. I check the code with my computer and said P0430 which is Catalyst system,Efficiency below,Threshold (bank2). I thought this was caused by putting in 87 and getting a bad batch of gas. I used some Lucas and after about a quarter gone, I filled up with 91. I then reset the ecu and light was gone for an entire week. I thought okay, problem solved. I just filled up yesterday and at my 76 which has been good to me with 87 and now the light came on when I left the house this morning. I do notice it came on both times early in the morning when it was cold out.

Has anyone had this problem?

Thank you!

 

It's not the gas. It's the converter.

After you reset, it takes x keystarts with a fault sensed for the light to come on. Just happens that your x+1 keystart was in the AM

 

Thank you for the quick response.

reading up on it, some say it can be

• Faulty catalytic converter
• Engine misfire
• Fuel injector leaking
• Engine mechanical damage
• Oxygen sensor that has improper readings
• Exhaust leak

But I think it is the converter like you said Bill.

 

Bank 2 makes me think it's the converter on the right side.

 

Oxygen sensor could be really common. I had 99 Nissan that had the engine light came on for a week and off for a week. Get a code reader then you can tell.

 

Same thing happened to mine, just go to rock auto and get both rear 02 sensors and you'll more than likely be good. I replaced at 90k and have 165k now, without cel coming on.

If you want to test it you can buy a spark plug anti fouler and drill it out and re install the old sensor. Put the 02 sensor back in and see if cel comes back on.

 

Sub'd

 

Bank 2 is driver side. Cylinder 1 is passenger side, therefore it is bank one.

Look for black soot around the flange where the header to y-pipe meet. Could just be aged gaskets leaking. If there is soot, replace both y-pipe to header gaskets.

 

Thank you all.. I'll look into the gaskets and O2 sensor. Cold morning start is when it came back on, which could possibly be the gasket is bad and cold air makes it way through. Taking it in Monday to have them check and fix. I'll post back with results.