Got a couple of P codes when my car went in for a lambda sensor change, but no engine light P0171 and P0174, which are system lean on both banks.

Done a bit of googling and I see it can be caused by air leaks in the system. One of the culprits can be the PCV, but before I change that, I’ve asked the garage to do a smoke test whilst it’s having the lower wishbones changed.

Ahead of the results, I thought I’d pop up a post and see if anyone’s had this and what they did to sort it.

Here you go

https://www.rrsport.co.uk/forum/topic59578-15.html

Many thanks - there’s a few pipes under the cover which could be the cause, so will see what the garage say.

Must say, I do love driving the 4.2, like you I’ll have a go at most jobs that would normally put people off these cars and it means you can get a cheap luxurious run about that doesn’t cost a fortune to look after.

Half way through installing the Overfinch leather interior. Back seats all done and looking amazing and then it’s on to the front passenger seat. Doing that one first in case I encounter any problems.

Also ordered some matched leather & vinyl paint from The Scratch Doctor so I can clean up some of the tired trim bits.

Turns out it’s a crack in the air filter housing. Need to fully investigate where, but nothing a bit of either superglue, plastic welding, or a replacement housing can’t sort out.

Apparently the crack is where the breather pipe connects to the large plastic air intake manifold. The car's back from the garage now, so I'm unable to have them point it out to me, so would be grateful if a kind soul could post up a pic or two of exactly what this part is. 4.2 SC.

Thanks as ever in advance !

Managed to get this sorted - the air intake ducting is part nr PHD500055 or 4619625903

Got one in perfect condition for £15 delivered, so just waiting for it to arrive.

That’s why cars of this age are great - parts are cheap and plentiful !

Update - all sorted ! New plastic intake manifold arrived, popped it on and air leak codes have now gone.

Probably the simplest, cheapest and easiest fix to date.