Hi, I bought a Volvo S40 2.4i recently. It has 107K miles on it and it has started to run very rough.

When you start the car there is a lot of vibrations (due to the engine mounts being toast I'm planning on replacing them if I can fix the car) and there are loud banging sounds at first until the RPM's settle down (~700rpm) it goes away. When you're parked and rev it past2000 rpm the banging goes away. (So the loud banging is between ~700-2000rpm (this is just a guess)). When I drive the car at slow speeds trying to accelerate there is banging but when you get past a certain speed it seems to settle down. also when I'm coasting there is virtually no engine noise.

I recently just replaced the PCV diaphragm due to it having that unique squealing sound. When I popped it out the diaphragm was definitely ripped and I put in a new one. It ran better (responsiveness) after that but that wasn't the main problem I'm guessing because it's still banging. I don't know if the PCV system is clogged possibly and if Liquid molly engine flush would help?

Another thing is I tried to put gas in it and the pump keeps shutting off. I know that either the evap hose connected to the charcoal canister is clogged or I have a bad charcoal canister which I have yet to get under and check. I don't know if something like that can cause my issue but I thought i should mention it, also if someone knows if this is a thing with the S40 please let me know.

Codes that show:
P0171 (Engine running lean)
P0455 (Large evap leak)

What I know:
Replaced PCV diaphragm ran better
Gas won't go in the car
Banging on acceleration ~700-2000rpm
Evap monitor fail
Fuel system monitor fail

I have attached freeze frame data and Modesix data in pdf

Please any help that you can give me would be much appreciated. I will do my best to reply quickly to everyone.

 

Are you sure that the "banging" noises aren't just from the bad motor mount? If there is metal-to-metal contact in one of the mounts, you're going to get some unusual noises.

Don't have much to add about the evap problem - I never had a "real" manual, so I'd be guessing... but you're on the right track and I'm guessing that the codes you captured will steer you in the right direction. You could probably just unplug the inlet hose to the charcoal canister - if the fill problem goes away, you've got your culprit (or to be thorough, if it goes away, and STAYS away when you unplug the outlet hose from the canister, meaning the canister is the constriction).