quick question. went to get my truck smogged in feb of 06 and had a code 25 stored. Toyota narrowed problem down to valves out of adjustment. and one was very tight. Ok I am getting that same code agian. The CEL will pop on stay on for about 2 weeks unless I pull the E.F.I. fuse right away then stays off for atleast a month but is bound to pop on at some point and its always a code 25. Im getting 16 mpg around town with a dirty airfilter and 33 inch tires (Thats very good). oxygen sensor was replaced trying to illimainate it myself before I took it to get valves adusted 20,000 miles ago last year. Mabye if u run some 91 octane thru it Clogged injector mabye. I tested M.A.F. sensor and it reads within specs. I dont know to go about cleaning it. What would u guys suggest?

 

Sounds like one of two things:

1. Vacuum leak somewhere in the plenum

2. Leak in your pre-engine/post VAFM (there is no MAF on these vehicles) intake tubing.

Incidentally, if you're running 33" tires with original gearing, 16 mpg is GREAT.

I would VERY surprised if valves out of adjustment caused a code 25. I think the dealer added a few expensive things along the way to pad his wallet.