Ok so new owner to the Volvo world and happy so far but have one issue that I don't want to throw money at everything under the hood and not fix the problem.


at take off I have little to no power till about 1500 rpm then goes very well,? also when at idle has bad vibration until I put it into neutral then idle will smooth out some people tell me that coils are the issue and others are saying that it is sensor and FPR? someone please help me.


it would be greatly appreciated

 

Sorry to hear about your volvo woes, we've all had our fair share

About the coils, I just went through replacing both of mine on a 2003 S40. (2000 through 2004.5 S40's were 4 cyl with 2 coils, if you have a later S40 you have 5 cylinders and I'm not sure about the coil stup on those).Symptoms were engine missing at low and at high rpm's, mid range was fine. This got worse the hotter the engine got, especially sitting in traffic. To test the high range get on the freeway or a road where you can get going around 55mph, then floor it. With my bad coils there was a very prominent engine miss when I did this. You also mention a rough idle. Two different types of roughness... One from an engine miss and one from worn out engine mounts. The miss should feel softer and irregular and the mounts will be more of a steady vibration coming through the steering wheel.

Unfortunatly the coils are almost impossible to test. You will read online about OHM tests and such... but these are pretty unreliable. A bad coil that still functions when cold and only misfires occasionally will still give a decent reading on a meter. You can visually inspect them, I had a fine crack running down the plastic post that goes to the spark plug.

If the miss is bad enough you shoud eventually get a CEL. Hopefully it will be a P0301, 2, 3, 4 or 5... meaning a miss in one cylinder or another. In this case you could swap the coil positions and see if the code moves to a different cylinder. If so then you can reasonably assume that its a coil causing the miss. I got a CEL about a week after the miss started.

Also, and I've done this woth other cars, if you can find a cool Autozone type employee they will usually let you try one out in the parking lot.

Another cheap and easy check would be your spark plugs. Pull each one and check the condition and gap.

 

What year is it? Mileage? How long have you owned it?

 

its a 01 Volvo S40 just broke 100k miles its not at all a miss in my engine that I am having, when it does get hot and the a/c is on for a while, when taking off it sputters and just about dies when a/c is not on just sitting at stop it acts likes it wants to die but the rpm never drops but maybe 50 rpm and is just rough like a vibration but when shifted into neutral at stop smooth as butter in idle at high speed when standing on it it goes great just getting to speed from a stop is a bit of a challenge till 1500rpm.