Hello all, I pulled two trouble codes.

DTC P1131 - Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1

DTC P1151 - Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2

Ironcially I had my upstream O2 sensors replaced about 2K miles ago after I got my truck custom tuned.

Anyone have any ideas why they would be causing an error? It's dark and cold out now so I haven't physically looked at the sensors but I'll take a look tomorrow. My gas mileage has also gotten significanlty worse.

Thanks in advance.

- Chris

 

Define "custom tuned".

 

Get it custom "untuned". It's screwed up.

Steve

 

sorry, I'll be a bit more specific. I got in on the group buy from Troyer performance and purchased the XCAL2. Based on my sheets, he recommended I change out my upstream O2 sensors since I was running on my originals. I've been running the 87 per. tune for sometime now so I don't think it has anything to do with my custom tunes.

I just thought it strange that after I replace my upstream O2 sensors they throw a code after 2K miles. Any ideas?

 

I agree!

 

Guys, I can't see how the tuning has anything to do with it. The truck has been tuned by Troyer Performance via the XCAL2 I ordered last year. I've been running like this for almost a year now.

About a month ago I had the O2 sensors replaced with new Bosch sensors and now a month later I get these codes. Guess I'll take it back to the dealship who replaced the sensors and see what's up.

 

..or contact Troyer for advice....

 

If the tune isn't doing it, then I'd guess you have a vacuum leak. Given that it's a 4.2 liter, I'd think intake gaskets and isolator bolts.

 

I'll give that a shot. I've been reading some about O2 sensors recently, could it be that the new sensors are just doing their job reporting the error and possibly my catalytic converter(s)? are bad? It's the original exhaust system with 87K on it. It does sound like I have a exhaust leak when I lay into the throttle so perhaps it's in my best interest to have the exhaust checked.

 

Chris,take those two guys advice;they are Ford techs and know what they are talking about!

 

I appreciate any and all advice given, especially from three of the more exp. members on this forum. I'm still fairly certain the custom tuning has nothing to do with my issue (or so I hope not). With this type of issue I think I'm going to leave it to the professionals at my local dealership. Thanks fellas.

 

I just changed my engine (messed it up with SeaFoam). I installed an engine with 110K miles on it and it runs much better than my other one did before I messed it up. But, 5 miles up the road it threw a code. Autozone read it as P1151. I looked it up and did some research on the Forum and everyone is saying "intake gaskets and isolator bolts". What is the isolator bolts? Not famililar with this. I reused the engine harness and vacuum lines. The rest is from the other engine.

 

I must ask. How did you mess up an engine using seafoam? I have used it for years in all types of engine, with great results and zero problems.

 

I think he introduced it too quickly into the engine and it hydro-locked.

 

Correct. Used the brake booster line and it sucked it in too fast.