Trouble Codes P0440 P0430 P0420

[Jason G.]

I posted in january that I had a trouble code 1349 along with trouble codes p0440 and p0430 and misfires in all cylinders. I have had the trouble codes p0440 and p0430 for awhile but the car ran fine and a few mechanics were not able to pinpoint the problem. When the trouble code 1349 popped up and the misfires, my mechanics put seafoam in the gas thinkin I might of got bad gas b4 calling it quits cuz they were not very familiar with the code 1349 OCV or VVT engines. I solved the trouble codes 1349 and misfires with a new OCV. But since then the injectors are louder and possibly have more engine noise. I have always been able to notice small changes in engine noises or changes in how all my cars drive. Usually has been an early sign something was going out and have gotten a jump on it. I have had this car since 2004 and my injectors have never been this loud and they have gotten louder since the OCV replacement. I have checked most of the hoses under the hood and have replaced 2 cuz of hardness or bein pinched. I have also replaced the gas cap and have checked the notorious airbox hose and it is fine. I now have code p0420 to add to the p0440 and p0430. Any ideas on what i might be able to check b4 trying another mechanic or possibly replacing the twin cat manifold which is a huge junk of change. Also since the OCV replacement I now have a small oil leak I have been unable to pinpoint that is on the drivers side of the engine, It is not the OCV or oil filter.Thx for any help

2001 Lexus IS300 183,000 miles

[IanH]

I have a 2004 and about 145K I started having the P0420 P0430 codes. I used a cheater to fix this. They are cheap and get the light off, I have passed emissions since I installed. Agruments against this vs an O2 Sim are that you still need a working O2, ie heater can and will fail at usual interval. Mine were $25 for two Stainless Steel made in USA. If you need a link let me know. O2 heater hasnt failed yet.

[Schmitty605]

those codes are for the catalytic converters: p0420-bank 1 cat, p0430-bank 2 cat, p0440 is the cat in the y-pipe. Dont recommend using sims which can cause further issues down the road, when i got those codes, i replaced the cats with aftermarket performance catalytic converters. i got magnaflow hi flo cats. spent a pretty penny but they were worth it