G2006 , 02-21-2024 12:57 PM
Senior Member
Freeze frame scan tool data. Someone please advise
Ordered a new bank 2 upstream o2 sensor. Haven’t had a chance to install it yet. But here’s what’s happening. P0171-0174 for months. Changed big 3. New brake booster. New fitting on intake manifold. Same codes keep coming back. Can’t pass inspection since last October!!! So almost a month ago. I cleaned the maf sensor and that seemed to get rid of P0171. Wasn’t even showing as pending. Yesterday checked codes. P0174 current. And P0171 pending again !!! I did a data log with freeze frame on my c-reader scan tool. Here’s what’s showing. Any help please on this. Sick of throwing parts and money at this problem and never gets resolved. Car starts and runs fine. Good gas mileage. I get the 3000 rpm limit when the check engine light comes on. Clear the code and light. And car flys over 3000 rpm with a lot of power to spare. Please help
to decipher this freeze frame data. Gotta get this fixed. Losing my patience. Thx for any help.

 

Do the trims drop if you rev to about 2500?

 

JagV8. Long term fuel trims increase when I raise rpm’s to 2,500

 

Not an air leak, it seems.

Had code(s) related to the O2? I'm wondering why you're planning to change it?

 

I actually have an upstream bank 2 I ordered. A Denso. Gonna have it installed. Any other advice brother ??

 

But no. No actual specific codes for an O2 sensor. Had this same code and problem two years ago strange thing is. My old mechanic changed our bank 2 upstream o2 sensor. And that got rid of the code for 5 months. And I paid $350 bux for an OEM sensor from Jaguar directly.

 

JagV8. Interesting thing happening. Not sure if this can be the root of my problem. Ok. So been getting the P0174-P0171 for months. As I said long term fuel trims increase in numbers when I rev the motor from idle to 2,500 rpm’s. About a month ago. I cleaned my MAF sensor. Cleared the codes and went for a drive. Check engine light comes back on during the drive. I get home and check with my scanner. Just P0174 current and P0174 pending and P1000. System not ready whatever. So I drove the car like this for a solid month. Everytime the check engine light came on I checked. And was getting only P0174 then. No sign of P0171 anymore or even it pending. That lasted about a month. A few days ago check codes again. P0174 current. And again P0171 as pending. I took the maf sensor out again and cleaned it yesterday. Drive this morning check engine light comes on. Again only P0174 code as current and pending. no P0171 code either current or pending !?!? Can it be possible my problem is a faulty MAF sensor ? Seems like when I clean the maf sensor it resolved P0171 at least for a few weeks. So far every other repair that was done to resolve this. Resulted in both codes coming back. Please advise and thank you for your insight.

 

Quick follow up. I went out and unplugged the MAF sensor while the car was running and it didn’t stall. Just kept running !?!??

 

It'll use default values when MAF unplugged.

Can't be worse than what you have (joke?). Bad MAF it might be. Could be clogged/destroyed cats due to using car like it for so long.

 

JagV8 and others. Please tell me what should I do now ?? I need to get this car inspected and want it fixed. It runs and drives great. Please need advice on what step to take next

 

 

Dell. Do you think I’ll be better off buying a Denso maf sensor ?

 

Coincidence ???? I cleaned the maf sensor again. Cleared codes. Next day jet just the P0174 code. No P0171 current or pending. Cleaning the maf is the only thing that cleared at least one code for a month. Gonna try a new maf sensor. I guess I’ll go with a Denso. That’s what’s in the car now.

 

I am in the same place as you are right now, and have been for months.

I would suggest hooking up th OBDII get it into live mode and spray it with MAF sensor cleaner, nothing else!!! I have used everything from carb, brake and either adn the rpm never changed. I sprayed it with the MAF adn the car dies on the spot, as if i poured water down the intake.

Get a smoke machine off Amazon and run it. The smoke found leaks that even the MAF spray couldn't. Right or wrong i ran the smoke machine up to about 28 psi which is more or less double atmospheric pressure.

i am going to probably going to start a link going a little deeper into this.

Good luck.