HI guys I have an intermittent issue with my single turbo fd, now it was running really nice, parked it up for few days then came to it was running fine but the afr changed slightly, started running slightly leaner on cruise ect nothing worrying but noticeable change, parked it up left it for a few hours came to drive home running perfect again,
Now parked it up for a week or so started a journey all was fine got about an hour into the journey and it picked up a stutter and started running lean on cruise limped it to a service area left it for an hour was fine, hour into journey happened again, managed to get where I was going, parked it up for the weekend came to drive home was fine for the 2hr drive home, you get the picture lol with the intermittent problem, thought it may of been a faulty lift pump so changed that was running really good again then few days later the problem came back, checked vaultage to pump that seems fine
When it starts to stutter afr goes up into 16's 17's so thinking it's a fuel side issue

Spec is
Single turbo
Half bridgeport rebuilt 2000miles ago
Spark plugs NGK iridium R7 420 10's
1650cc secondaries
1000cc primaries
Bosch 044 external fuel pump
Swirl pot
Braided fuel lines from fuel tank
Torques high flow fuel filter
Custom engine loom
AEM coils and new coil loom ect

Any ideas on what could cause the intermittent problem if you need any other details or spec let me know

 

What Wide band?

When was it Calibrated last? How new is it?

How old are those INjectors?

Check Fuel Filter and in tank Pump Socks

 

Innovate wide band not quite sure on the age, sock is fine as the lift pump was changed, need to check the fuel filter injectors are the old style Bosch 1650's which are going to be changed

 

I also think it's your o2 sensor. It's too close to the turbo and is being eviscerated by the high EGTs. I have mine right at the tip of the midpipe as do most other people running a wideband. Plug the existing bung and relocate your sensor or you'll just keep eating up o2 sensors.
Twice in one day I made the same mistake of replying to the wrong thread (suggested thread at the bottom)... It appears I need some coffee. Sorry for the pollution.

 

Try running a few bottle of techron fuel system cleaner through the system. Maybe an injector is sticking or clogged.