My 3.0 is running rich- at least that is what the error codes are saying. I noticed a big drop in gas mileage- 240 miles per tank to 140 miles per tank. I keep getting the CEL when I am idling. I keep pulling the EFI fuse and that clears it, but it will come back when I am idling like at a stoplight or something, but not when I first start it up in the morning. I heard somewhere that the injectors like to start dribbling fuel when they are old and worn out. I imagine that could cause a rich condition. Anyone know how much it will cost to get the injectors rebuilt or replaced? I have replaced both O2 sensors at $120 each already and no improvement! I am out at sea in Southeast Asia right now, so I can't get it fixed until we get back home again. Thanks in advance! :help:

A local shop should be able to rebuild them for you, if you can't find one, Downey off-road charges about $250. I had mine completely rebuilt/balanced/flow tested for $35 each locally. Have you lost power as well as mpg?, if so, you could have a stuck/burnt valve.

What type of o2 sensor did you put in?
Bosch or OEM? if bosch that may be part of the problem.

What codes are you pulling?

I replaced the O2 sensors (2-CA truck) with OEM ones, which surprisingly came from Schucks. I can't remember the exact codes that I pulled, but I have a commercial code reader (it is just a commercial device that shorts the T1 and E1 connectors together. The book that came with it indicated that the codes are for running rich first, and then running lean afterward. I did lose some power, but around the same time I had to replace my tires (31-10.5-15) with some slightly wider ones (31-12.5-15) and I didn't think that the power loss could be attributed to something else. The significant loss of fuel economy was what concerned me above all. I mean my truck can still get up to highway speeds, but I need to push the pedal that much more. The power loss was most noticable when I am in 4-HI. My top speed in 4-HI used to be 50mph. The last time that I had to run in 4-HI was in January and my top speed was like 35-40. I am weighing my options right now between rebuilding the 3.0, swapping to a 3.4, or the Tacoma 2.7, or just selling the truck and getting an older Toyota with the 4 cylinder. I have all the time in the world to ponder this since I won't be back home for a little while longer. (I am on deployment in SE Asia at sea right now) Thanks for the replies, and if you have any other great ideas, please share them. Thanks.

$40 Bosch Universal 4 wire O2 sensor will do fine. just solder/heat shrink the harness off your stock O2. Done it to many cars and trucks. As for the injectors... i got a whole set for $117 from some guy on here!! all of them were in bags, rebuilt and bench flow tested!! what a deal i got. don't forget the square cut O rings for the injectors. and the upper gas O rings. Otta Git-R-done.

This would be code 25 and 26, my 4runner gives the same codes. I have seen other posts about this with little answers. Several people replaced 02 sensors and it didn't help. I believe my tps(throttle positioning sensor)may be the problem. Im going to try cleaning or replacing it. I read somewhere that a bad egr could be the problem too. If u get the answer let me know please please!! Thanks Ray blurpps@msn.com

Well I got a reply on the Yotatech forum regarding my problem. Silvertaco stated that his father's 4Runner had the same problem and it ended up being a burnt exhaust valve on the #4 cylinder. Obviously this will involve removing the heads, but what will be involved with repairing this? Cost?

If it is a burnt valve, and you can't(don't want to) do th work yourself, figure on about $1500+(they will only fix the bad valve, you don't get all new valves). If you want to do the work yourself, you could could have both heads rebuilt, get new gaskets, sensors, and have all of your injectors cleaned/rebuilt for under $1000. I have had to do fix burnt valves twice, once through the dealer for $1700(1 of the odd side valves), the second time I rebuilt the top end myself(had a burnt #4) last April. For the same amount of money I would have spent at the dealer, I basically got two new complete heads, all of the gaskets/sensors, and headers/ exhaust. You will definately get more for your money if you can/want to do the work yourself. You should have a wet/dry compression test done first, this will tell you wether or not you have a valve problem.

Wet/dry compression test? I have a compression gauge and am about to test my engine, how would the wet/dry test differ?