I bought my son a 1996 Volvo 960 one week ago. It has 200,000 miles. When I bought it, it idled pretty rough, but ran great...had good power, sounded good, but the engine light stayed on....so I took a chance. After I bought it, I took it by and got the code checked out. It said misfire in #4...he said it probably just needed a new spark plug. So the next day I took it to Precision Tune and got the tune-up, oil change, and the A/C recharged. He called to say that the tune-up didn't seem to help, that it probably needed the ignition coils. I told him to just hold off on the ignition coils. When I went to pick it up, he said he had tried the new wire and checked the compression and that #4 had very bad compression and that the ignition coils wouldn't help and that the engine is pretty much on it's way out. When I left there the car runs terrible now. It knocks at first and constantly hammers and has much lower power and the check engine light flashes now. We then found this forum and thought perhaps they had just used cheap plugs. So I purchased the tri-electrode plugs from the volvo dealership and we installed them today. It is maybe slightly better, but still pretty bad. I took it for the codes and it came up with P0304 (cylinder misfire detected-cylinder #4), P0300 (cylinder misfire detected - random cylinders), and P0305 (cylinder misfire detected - cylinder #5).
Any ideas on the problem??? What do you think could have changed things so suddenly? Did it possibly have some additive in it that was making it smoother? I don't know if it is worth fixing or if I have a money pit. I just need a year or two out of it to be my son's starter car. Any help would be GREATLY appreciated!!! THANKS