The PO says he replaced the o2 so I had the exhaust gone over, to try to find the reason for this lean code.

After the exhaust leak was fixed, the light didnt come on all day yesterday but today its back.

The code shows h44, but the light keeps coming back. I tried the method of using trip reset/trip odo and eng met to clear the h codes. The next time I checked I saaw h72 and h74. Tried clearing it again waited for a while restart ran the engine let it idle cel on again a minute after starting to idle. Checked the codes only h44 this time again. Dont know here the h72 and h74 went to or where they came from never saw them before.

Sit in the car listen to it idle, its high about 900 warm, pretty sure theres a vacuum leak.

Listen for a few minutes, heard a very slight rev on its own that lasted a second or two. Sure enough on goes the light. Turn the engine off wait, restart listen to it idle a minute later very slight surge and on goes the cel.

Can someone help me get this sorrted out please.

Everything about this code appearing seemed intermittent, so I decided to start an investigation. I timed the occurence from a restart, three times to see if it took the same amount of time to occur or not.

All three times it was at 1:43 in from a restart. Maybe not so intermittent now. But I still have no idea where to go now. Is there an emmission system that gets commanded on about 100 seconds after a start?

 

AIR system possible you could disconnect the hoses from check valves. If AIR doesn't divert the air from manifolds the O2 will go lean and code will set.

 

Can I remove the hoses and drive it to test with them off

 

Yes it should be ok. Make sure check valves are not allowing exhaust to blow back. Most likely they aren't. When they do it can burn a hole through hose.