zippinbye

[QUOTE=mitsuguy;6800169]Zippin - you HAVE to drive for some time, a day or two, without clearing codes... QUOTE]

Mitsuguy, good steer on this concept! While the 4 codes in orginal post came up after 15-25 or so drive miles, I got 2 addtional codes by leaving the codes uncleared and drivin a lot more. You prediction for code #s was close - excpet it looks like a "large" EVAP leak; P0441 and 0455, "EVAP Emission Control System Purge Flow Fault" and "EVAP Emission Control System Leak (laRge)"

I'm going to review anything I may have disturbed underhood while doing the alternator. And a gas cap. Report to follow. Thanks for all the input.

zippinbye

I inspected every emissions- related ltem that I disturbed during the alternatior install: air intake housing-to-throttle body ducting, passenger side valve cover breather to said duct, and a similar connection from a tube that runs to the power steering pump (a co-located tube runs to the back side of the throttle body, not sure what these two tubes are). They all appeared undamaged and properly seated/clamped. Nonetheless, I pulled all items apart, looked even closer for cracks or other obvious problems. Non found. Reassembled, with extra emphasis on seating and proper, firm clamping. Looks good. Local auto parts store had to order the fuel filler cap. Checked Stant catalogue at Wal Mart as an alternative. GX 470 only Toyota/Lexus not represented! Noticed that every Toy/Lex from about 2000 on using the same cap, a $4.80 item. So I thought "how could it be any different?" Question answered at attempted install. Purchased cap has threads, GX cap basically uses a double tab affair that must rely on a tapered flange on filler neck for tightening ... incompatible. So it's off for a drive with codes reset, underhood tweaking, and no other changes. Hopefully the fuel cap will be in and I'll swap it on before more codes come up.

CruiserGX

Get the cap OEM cap from Toyota or Lexus ~$24.

zippinbye

Added new gas cap and checked charcol filter lines as suggested by Mann777, along with underhood connections that might have been disturbed during alternator install. Reset codes. The came back in a drive cycle. Given that one of the codes indicates "EVAP Emission Control System Leak (laRge)" does anybody have a suggestion of the most likely source for a LARGE leak? Again, this is so coincidental that the codes started triggering right after alternator work. But of course coincidences happen all the time. Just trying to elimante what I can as a shade tree mechanic before I get the pros involved.