DTC help - 1151 and 1131

So I finally got a different DD and have not been driving the Stang too much, but the last two times I took it out I have been getting codes after a while of driving around town.

The first time I got the codes, I only got one (it was one of the two but forget which one it was). I just cleared the codes and was fine for the next 3 times I drove it.

Today on my way home from work, the SEL came on and I got the 1151 and 1131 codes. Saying something like "Lack of HO2S11 switches, sensor indicates Lean Condition, See 2197/2195)

I have not made an recent modifications, last one was 4 months ago when I put on my X pipe and I have put a few thousand miles on it since then.

From searching I see that the codes might be related to O2 sensors, but seems they are on different banks.

Car has about 92K miles on it.

Suggestions?

~K
 
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So I finally got a different DD and have not been driving the Stang too much, but the last two times I took it out I have been getting codes after a while of driving around town.

The first time I got the codes, I only got one (it was one of the two but forget which one it was). I just cleared the codes and was fine for the next 3 times I drove it.

Today on my way home from work, the SEL came on and I got the 1151 and 1131 codes. Saying something like "Lack of HO2S11 switches, sensor indicates Lean Condition, See 2197/2195)

I have not made an recent modifications, last one was 4 months ago when I put on my X pipe and I have put a few thousand miles on it since then.

From searching I see that the codes might be related to O2 sensors, but seems they are on different banks.

Car has about 92K miles on it.

Suggestions?

~K

exhaust leak near the midpipe?
 
Well I pulled my plugs last night and they were all WHITE, looks like she was running hot / lean. I was running a step colder plug NGK TR-6, but this time I went back to the NGK TR-55's.

Could the TR-6's been causing my engine to run lean?

Since changing the plugs, car seems to run fine but have not had that much run time yet. Got a long drive today so I'll see how she acts.

~K
 
1151 is dirty mass air flow sensor. buy some maf cleaner and pull it out and clean it. if you have k&n air filter or one that requires oil, you'll get this code every time you re oil it most likely.

1131 is right bank running lean. if it was your plugs I would think both banks would run lean. change the front o2 sensor and that should solve it, unless you have an exhaust leak in front of that sensor. as someone told me even a pin hole leak you cant hear can cause that code. mine went away after changing that sensor. it was $43 I think.:nice:
 
Well after the plug change and MAF cleaning the car seemed to run good. Took it to work, then to drove down to Charlotte (3 hours) over the weekend and then back a few days later and no problems. Then backed out of my garage and left her running in the driveway (which is on an incline) as I moved my Jeep and when I got back in I see the SEL light is back on. Check and they are the same codes...again.

Could these codes be related to only have a little bit of gas in the tank. Seems to show up only when I have 1/8 of a tank or less. Maybe I got some crap laying around in the tank?

Also started playing with my predator and data logging and saw my TPS reading were nothing or WOT (see other post about that) even with the lightest touch of the pedal.

So I backed-out some timing off my tune and went to re-flash and the flash failed. After finally getting the stock one back on and re-flashing (Had to do it twice) with the modified tune the car seems to run A LOT better for now. Been on a few drives and no light yet.

Could something of got messed up on the old tune and been causing this problem?

~K
 
Well after a few more drives, the light came on again.

So I started checking all my vacuum lines, and found a crack on the bottom of the hose that connects to my PCV valve. Which might also explain why I have been seeing some oil on that side of the engine. Did not notice it when I changed my PCV valve about 6 months ago.

I also checked all the bolts on my plenum, TB, IAC, and EGR and a few were slightly loose, took like 1/3 turn to snug again, so maybe there was a leak there too...

First few drives seemed to run great. Notice a little smoother idle and no light yet...Hopefully it will stay like that.

If this does not work, was thinking of taking it to a shop since I need a new tune agian (lost my old one on a failed flash) and having them data log it and see what it might be. Would that help find the problem?

~K