Help! I have a wideband lambda fitted to monitor fuelling, last few weeks it is showing lean numbers, as follows:
Start in the morning it's 14.5, stays like that on warm up.
After a few minutes/miles it drifts to 15.8, it's 20/21 on the overrun, and I'm too afraid to hit boost.
It used be lower all over.

And it's not the gauge is wrong, as its popping much worse on the overrun, and won't idle after a few minutes, I've to give it throttle to stay running.

It's running standard boost, Unmodified except front mount and exhaust.
I tried a different TPS but to no effect and I don't think it's a boost hose leak.

Any ideas? Starting with the cheaper fixes!

 

What's it like on boost? Or on the move

 

Lean, it used be 14.5 or so on steady off boost throttle, now it's high 15s, I'm too afraid to put more than .1 or .2 of a bar pressure through it, it's just doesn't seem right. Coming up to traffic lights or a junction I need to give it throttle to stop stalling.

Nothing has changed in the last few weeks. I had the intercooler off to change the rad a few weeks ago, but the problem didn't happen straight after this, it was maybe 100 miles later. I don't use the car everyday, but I do need it every now and again

 

Still sounds low before you had issues, needs setting up

 

Rocker was abit loose, appear to have fixed it.

It definitely needs setting up, hard to find someone over here you can trust!