Chadr7850

Hey everyone I just bought a 96 2.7 l that has 131000 miles. When I bought it, it had a check engine light on for p0171 lean fuel mixture on bank one. The truck ran totally fine got it home no problems. I had taken off the battery cable to reset the computer and now it has no light on idles totally fine but when I drive it, it has no power sputters and runs rough. I was wondering what you guys think could be the problem. I have checked the maf and it's clean and the throttle body looks a little dirty but not horrible. The air filter is dirty and will replace it tomorrow to see if it help what would you guys do?

rworegon

Straight from the Toyota manual:

P0171 System too Lean (Fuel Trim)
Air intake (hose loose)
Fuel line pressure
Injector blockage
Heated oxygen sensor malfunction
Mass air flow meter
Engine coolant temp. sensor

That should get your started on places to focus the troubleshooting.

KryptoRoxx

I would start with some seafoam treatments. Quarter in the fuel rank, quarter in the oil, quarter into your vacuum lines. Drive that tank dry and then after 500 miles or so change the oil. For the vacuum line let the engine suck it from the bottle and then shut the engine down for a few minutes. Turn it back on and let it idle till the smoke clears.

You might find mixed reviews on this stuff but I trust it in my yotas.

Chadr7850

Hey thanks guys for the help, cleaned throttle body maf replaced o2 sensor and it's back to running like a champ other than the pesky light came back on before I cleaned tha maf, hesitant to reset it, ran some amsoil pi through tank and brake booster to clean it out going to get some sea foam to help it out even more, what do you guys run the sea foam through? Just the brake booster or is there somewhere better to run it through. Last question- when ever I seam to open it up theres a sulfur smell thinking egr valve, my 09 4tunner does the same thing what do you guys think

KryptoRoxx

I run seafoam through the vacuum lines that attach at the top of the intake manifold.

Could be a clogged egr but I have never had that issue.

Chadr7850

Well the brake booster runs through the intake manifold idk about the 3rz motors there isn't much to pick from

KryptoRoxx

I usually pick one of the smaller ones as it is easier to keep the engine running while sucking down the sea foam