Originally Posted by yert33

My 2004 SR5 has never had a valve job, timing chain or rings replaced AS FAR AS I KNOW. I bought her at 140K, 320K now.

Have been chasing and "solving" lean bank 1 then lean bank 2 then lean bank1 for a couple of months now. By solving I mean replacing the cats, servicing the injectors, then most recently replacing the bank 1 downstream O2 sensor. New shop (to me) did a leak down test and reported that #3 probably needed rings. They recommended replacing the engine in light of the high mileage and that I want to keep the vehicle as long as I can. (The rest of the vehicle is very clean and functional. Knock. On. Wood.)

I don't mind replacing the engine as I suspect that the timing chain, valves, etc MUST NEED some attention just from the number of miles on her. And it's been 1200 miles since the last "fix", the O2 sensor, was made. No CEL since then. The fuel trims are little higher on bank 1. And she is running great at the moment.

Question: Drive until it gets bad enough to replace engine or be proactive and bite the bullet now?

Discuss....