So I have done a ridiculous amount of work on this car/engine. 157K+ miles.

Pretty much I have a check engine light (P0171 & P0174 there was a 3rd code I forgot, but went away after changing my o2 sensors) and my car hesitates on acceleration and misfires. I get random surges of acceleration and my idle is very rough.

Here is what I have done in the past two months to try and fix it.

- Replaced Spark Plugs
- Replaced PCV Valve
- Found three vacuum leaks and resolved
- Replaced the o2 sensors and a/f sensors (These were ridiculously hard to do I almost decided to sell my car )
- Changed the filter of course
- Cleaned the throttle body and replaced gaskets of course

After all of that my idle wasn't rough and the hesitation was not as severe as before, but I still experience it and my check engine light came back on after a reset with the same codes. I am out of possible solutions. If anybody can shine a little light that would be greatly appreciated.

 

Causes of the P0171 code may include:

• A faulty fuel pressure regulator
• A weak fuel pump
• A clogged fuel filter
• A faulty powertrain control module
• A vacuum leak
• Faulty injector(s)
• Faulty oxygen sensor(s)
• A faulty mass air flow sensor

Common Problems That Trigger the P0174 Code:

• PCM software needs to be updated
• Vacuum leaks (Intake Manifold Gaskets, vacuum hoses, PCV hoses, etc.)
• Mass Airflow Sensor (MAF)
• Plugged Fuel Filter or weak Fuel Pump
• Plugged or dirty Fuel Injectors

I am going to say replace your MAF sensor with a Denso part. Don't use one from an auto parts store.

It solved this exact problem on my 02.

What part of TX are you in if I may ask? I know a great Indie lexus mechanic in Garland.

 

Forgot to mention, I did replace my MAF sensor, but that was a few years ago. I did however clean it. And I am in Plano. Not too far from Garland actually.

take your car here:

JP EURO
3521 security st.
Garland TX.

www.jpeuro.com

call them and as for jason, peter, or austin. Tell them Josh Morrison sent you.