Clunk at 1700rpm

Started as a slight hesitation when shifting, I thought.  Progressively got worse and really bad in Teton NP.  Found bad spark plug.

Check Engine light on during 3600 mile road trip

OBD2 codes

420 (catalytic converter - bank 1)

From tacoma blog:

Hi!! 

I've been reading A LOT on this P0420 problem and found out a few good thing you might like to know!!!

I lot of people have the same problem that we do, some changed everything related to emission system. Cats, o2 sensors, MAF, MAP, Temperature Sensor and still had the light coming on!!

On thing that not a lot a people think of checking is the Ethanol rating in the gasoline they use!! Toyota tacoma are set to use Gas with less then 10% ethanol... So what i did is I empty my tank and filled it back with ethanol Free Gasoline, unplug the battery to erase the codes and Guess what, no more light...

The problem with ethanol is that it doesn't burn like regular gas at all and our O2 sensors do not reconised the exhaust gas so your check engine light turn on!!!

I was using Gasoline that had 12% Ethanol and didn't know it!!

Try that and let me know what happens

Thanks

 

441 Evaporative Emission Control (EVAP) System Incorrect Purge Flow

from: 

https://parts.olathetoyota.com/p0441-code-toyota

However, before you dive in and start testing, it's a good idea to try a basic test: Remove the gas cap, check for dirt, grime or other items on the O-ring inside and the fuel port it seals to, as a broken seal in this area can trigger the P0441 code. Also check the "seat" of the cap on the filler port to be sure it is tight by simply screwing it into place until it "clicks" and then tugging to see if there is any give.

217k Timing belt, waterpump, seals, belts - no thermostat; $1500 @ One Toyota of Oakland

Old parts looked good.  Water pump did have some weeping, but everything was still working at the time of service.  Low ball quote of $1000 then added in another $400 in various parts during inspection (belts, tensioner, idle pulley, etc.)