WetbehindEars

Hey Everyone,
Im a brand new poster, so hope im in the right section here. I just purchased my son a brand "new" Runner (he has a little of a year before hes 16). Owned the truck less than 48 hrs but theres no time to waste. I have little to no background history on the truck, besides I took my time shopping for it. Specs: 89 3.0L 4x4 Runner IFS 120K the one pictured in my avatar. Im 2nd owner. Overall the trucks in great shape. Few ding and dents, but rust free, AC works, original radio still works, ohh the power steering pump is in-op. No Lift No Mods other than mid 90 Tacoma rims. After we purchased (had engine light on already) I checked the fluids and headed for the house (about 40 miles) I stopped and filled it up and noticed the gas cap some major pressure blow out when I opened it. After I got home I did the code check by counting the lights and came up with Code 25 & code 26. According to my manual thats Air-Fuel Ratio Lean Malfunction & Air-Fuel Ratio Rich Malfuntion. Just wondering if anyone 3.0 experts can point me in the right direction.
I plan on doing a full check on the truck this weekend, timing, compression, full tune up, ect. I will update with some pics after that... gotta get her cleaned up to show first!

toyota4x4907

The air escaping the fuel tank when you open the cap is normal. Its just the pressure releasing

25- air fuel ratio LEAN malfunction-feedback compensation or adaptive control value feedback is abnormally high. Open circuit in oxygen sensor signal.
26-air fuel ratio RICH malfunction-feedback compensation or adaptive control value feedback is abnormally high. Open circuit in oxygen sensor signal.

nv4runner

I would clear the codes out first and see which ones come back. I'm still slowly working on my code 25. To clear them remove the 15 amp EFI fuse for about 30 seconds. Put the fuse in and thats it! Drive it till the light comes on and you'll know for sure that it hasn't been fixed already and you can go from there.

toyota4x4907

right. good point. Is it running crappy?
Actually, IMO, its better to pull the + cable off the battery than pulling the EFI fuse. Take the + cable off the battery for like 30 seconds or so.

OutlawMike

The first place to start would be, as said above, clear the codes, see what comes back. If they return, then start with the O2 sensor. Get one that plugs right into the factory harness, do not get one that splices in.

I bought my rig with 125k miles 3 years ago. It threw a code shortly after I bought it, I think it was one of these two, anyway, the O2 sensor had never been serviced, it was past due.

Good luck,

Mike

WetbehindEars

Thanks Guys,
I will pull the battery cable this afternoon when I get home and reset the codes. Not really running crappy has a little bit of a rough idle but I have not even done the tune up yet. Also, the stickers on the truck went out 6 months ago, so Im pretty sure the fuel in the tank is as least that old. She doesnt smoke, but does have that "bad cat" smell at first startup. Anyways, I will reset the codes and follow up on the posting aftersome driving and a tuneup this weekend.