High Long Term Fuel Trims OBDwiz

[Number4]

My sons ‘04 4.0 has been having drivability issues. It had a bad cat converter, which was replaced (both sides), then the bank 1 sensor 1 O2 wasn’t reading okay, so it was replaced. At the time, bank 1 Lng Trm Fuel trim was 15 and bank 2 was normal. After replacing the O2, both long term fuel trims were high.

Using FORScan and OBDwiz, everything seems to be passing, but there’s a random misfire and misfire at startup.

OBDwiz is showing a fail under $A1 TID $83. Value = 1.0636 with max being 0.9995.

Each cylinder shows as passing, but they all show misfires in the last drive cycle, by varying amounts. The misfires also seem to be occurring at idle.

 

[Number4]

To update.

We replaced the intake gaskets and throttle body gasket. Afterwards, the short term fuel trims went to crap. Took it to a shop and had a smoke test done. They found the EGR was leaking. Replaced that and the fuel trims went back to how they were.

Bank 1 long term sits at 15. And bank 1 o2 sensor 1 keeps reading around 0.008. I’m leaning to a leak at the pipe to manifold. Probably taking it to a different exhaust shop for an unbiased opinion.