gtfourdreams

hey guys, i just purchased a few weeks ago an 89 4runner with 185k on it. a few things about it, it's a 3.0 V6, 5spd, 4WD, non-SR5 (no power nothing) 4runner. runs great so far. the last owner rarely drove it for the past year, so right after i brought it home, i put in some STP Fuel Injector cleaner. (i usuall use valvoline synth fuel injector cleaner, but STP stuff was on sale.) i changed the oil with Valvoline High Mileage 10w30 5qts. replaced the oil filter with a K&N, and replaced the air filter with a regular Fram.

i was on the highway the other night and noticed the CEL coming on. i checked it, and it gave me error 25 (engine running lean) and 51 (no idea). so any ideas on why my car is running lean and what code 51 means? if anything, it should be running rich after the fuel injector cleaner.

also, the car hesitates a bit in before 3000rpm. flies after 3000rpm, especially 2nd and 3rd gear. the car is all stock, with the above maintenence and has a newer cheap NAPA 2" exhaust from the cat back.

gtfourdreams

btw, wanted to add that i checked already checked all the hoses and they are all in place. after i reset it, it came back on during highway driving 5th gear, under cruising conditions.

also, where the heck is the EFI fuse!?

gtfourdreams

*bump*

AgRunner06

The lean condition is probably from the O2 sensor or a vacuum line.

Your code 51 is for a switch signal. One of the trouble areas listed is the TPS sensor. Your hesitation is a symptom of a bad/misadjusted TPS. So I would check that out.

The efi fuse is in the fuse box under the hood.

That should point you in the right direction.

:bounce2:

gtfourdreams

any idea on how i would "adjust" a misadjusted TPS sensor?

and as for the fuse, thats where i thought it should have been. (all my other toyotas have one there) hmm... ill look again.

AgRunner06

The web page I normally send people to is down so you will have to pick up a manual somewhere. Setting it involves checking the resistance and adjusting it to within specs.