Hello forum,
I have been receiving the P1136 Long term fuel trim, add fuel bank 1. System to lean code. The only drive-ability problem is at low RPMs when I come to a stop they jump up from 1000 to 1200 RPMs. I have replaced the Mass Air Flow sensor, so I figure I should check for a vacuum leak next. I have previously needed to replace the vacuum suction pump and elbow tube which extends from the back of the intake manifold after damaging it I thought I might just go ahead and replace the O2 sensors, however after reading other posts I found that I may have a small vacuum leak. So, my question is if anyone who has had this specific drive-ability problem knows where the vacuum leak may be coming from and how I can check for it. Any advice is much appreciated. Thank you.

 

If it is a leak, it could be coming from anywhere. Your best bet is to turn your car on, stick your head in the engine compartment and listen to try and locate it. Or else you can physically inspect every hose, but that's easier for some vacuum hoses than for others.

 

If it's a vacuum leak, start the engine and spray carb cleaner around all of the vacuum ports/lines. If the engine stalls/bogs down, you know you have a leak.

Since you're running lean, I'd also replace the fuel filter if it hasn't been done in a while.

Hope that helps.

 

I have checked the vacuum pressure and I get a steady reading of 19-20in/Hg at the intake manifold, which is right in the middle of the 17-22 range... does this mean I can rule out a vacuum leak?

 

Is there some way I could check the O2 sensors as well?