I just started having a problem where my 2000 Volvo S40 sputters when I go to accelerate. I need to "carefully" accelerate and once it reaches speed (i.e. highway) it seems fine. Also, when I come to a light or stop sign, the car will sputter. I usually put it in neutral to stop the problem but it starts again as soon as I place it in gear. The car hasn't stalled/stopped completely but after a half day of this (about three trips) the check engine light came on. Any ideas on what this could be? Some other sites mentioned possible throttle body problems but I'm hoping it's not that *** it seems costly and possibly common for some Volvo models...thax in advance...

 

The 2000 S40 does not have a electronic throttle body.
First you will need to have the codes pulled.

Just by guess I would have to say either a bad Mass Flow sensor, Coolant temp sensor, or bad coils.

 

Thanks for the reply. Two days before taking it to the dealer for an apointment I filled the gas tank up. The light went off the next day and I cancelled the appointment. I know that the gas cap can cause the check engine light to come on but since this is a new gas cap (about a month and a half old) should I assume the cap is faulty? Or can "bad" gas cause a check engine light?

 

Many things can cause the light to come on. Just because it isn't on at the moment doesn't mean the fault isn't there.

The code will still be in the system. You should still have the codes pulled.

 

Finally got a chance to pull the code - P0302 (cylinder 2 misfiring). Does anyone know the shop manual procedure for this code? Or should I start with the "obvious" - fouled spark plug, bad coil (as tech suggested), clogged injector, etc. The car still occassionally "stumbles" but mainly at low speed or from a dead stop on acceleration. The light was on twice but has gone off. Same code both times.

Thx for all the help...

 

Plugs/Coils/Injectors are the order I would look at it.

 

I have a similar question I to have a problem with the stumbling i replaced the plugs about 6 months ago with some ngk's. I've been reading that aftermarket plugs just dont seem to work as well as the volvo plugs. I'm also experencing heavy smoking under heavy acceleration. I was wondering should i just go ahead and replace the coils and hope thats the problem. Or could this also be a potential oil leak.

 

If one of the coils are missfiring then you will smoke.
I would say change the coils.