Sorry about the length of the post but I feel its important you know the whole story.

Hello all hoping someone here can give me some advice on an engine shudder issue. My gf drives a 2002 V40 Wagon. When we bought the car it ran great. 2 months after buying it it started to shudder under high acceleration. When she finally moved back from school it had gotten much worse. 3000rpm is a bit of a struggle for Benny (cars name), but slow acceleration up to 3000rpm and higher he is fine. (original code was a misfire in cylinder 2 and 3)

So to fix this problem I changed the plugs, changed the coil and the wires and because it had been misfiring for so long I changed the cat and the O2 sensors just to be safe and low and behold..... still did it.

So I dealt with it and I moved her from Michigan to New Mexico for work with the V40, a rather tense drive going up some hills. Getting on the freeway on a few occasions the engine cut out from the shudder and misfiring. A very safe thing to happen when merging....

2 days after I left her she took her car to a Volvo dealer and they gave it a check up and told her that its because I didn't use OEM parts. well she left there and got 2 blocks and the car shook so bad from whatever they did to it she stopped the car and turned it off because she was freaked out. She got it back to the dealer and I got to pay $650 for new OEM plugs, coils and wires and guess what her car still does? Shudder like a shirtless skinny kid in the snow.

I thought about trying to take legal action against the dealership that did it but I probably wouldn't get very far. So to this day the car is still doing it and I know for a fact that it does not matter if you have OEM parts or not. I have a 2001 S60 with 180,000 on the old boy with aftermarket plugs and 2 aftermarket coils and runs like a stabbed rat.

What would cause the engine shudder? Fuel injectors? Bad computer?... Please help as I am driving her back to Michigan at the end of May.

 

What fault codes are currently stored on her since the dealers efforts?
Try temporarily unplugging the MAF sensor and see if she runs any different.