Hi, I have a 01 S40 and everytime I stop it boggs but when I take off it's ok. The engine light was showing code 128 and I cleared it but still have the problem. I read on one of the forums that the bogging is related to the thermostat. Could this be possible? Or would I have to change something else? Any help would be appreciated. Thanks

 

I'm assuming P0128

From my sticky FAQ thread:

My dealer pulled a P0128 error code. What is this?
-This is the infamous "Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)" code. The solution involves replacing the thermostat with a brand new OEM one. If the code recurrs you may have to replace the coolant temperature sensor, but try the thermostat first. This code is frequently recurring with the early S/V40's. Many owners have sadly just had to learn to live with it.

https://volvoforums.com/forum/volvo-s40-11/frequently-asked-questions-34712/

You need to fix what is causing the code first and then clear it. You can clear the code, but the problem is still going to be there. Fix the thermostat and then reevaluate the situation.

 

I changed the thermostat and cleared the code. The engine still boggs when car is stopped but CEL is not on. What else can I check? Should I changed spark plugs or could it be some kind of sensor? Any help would be appreciated. Thanks

 

What do you mean by bog? Do your RPM's go way down to ~600? Or something else?

 

Yes, sorry rpm's drop

 

Mine does this too when it's cold outside.

You can try cleaning the IAC (how to link in my FAQ) that usually solves the problem. I pretty much just attribute mine to the cold weather.

 

My CEL is on and it's giving code P0015. Could this be related to the rpm's dropping?