I recently purchased a very clean 1995 945T from North Carolina with 231,000 miles on the odometer from a e-bay seller. The car has a hesitation/skip that is unfamiliar to me. I used to own a Volvo repair shop in Vermont which I sold 8 years ago to move to Pittsburgh so I am somewhat familiar with Volvo operating systems, although I am a bit rusty by now. I am wondering if anyone out there may have some help on this one. These are the symptoms as nearly as I can describe them. When first started, good smooth idle. Within a short time, maybe a minute, the idle gets rough and acts as if there is a skip. If the engine is throttled up to say, 1700 rpm, it holds there for a few seconds but then drops 200-400 rpm and surges. Put the car in drive and accelerate away and the surge causes the car to buck and jerk; not dangerous but very annoying. Once it is up to speed on a the highway 50 and up, the surge is only barely noticeable.
I have not had much time to really get into the problem, but I did some very basic checking which has not proved fruiful yet. At idle if I pull #1 spark plug wire, there is not much difference in the idle, it is still rough. Likewise when I pull #1 injector wire, idle still rough. All the other cylinders make a noticeable difference when wires are removed. This indicated a skip/miss in #1; I changed the plug, plug wire, injector with used ones of known good quality and checked the injector wire with a noid lite. Same problem. And that is as far as I have gotten. I will check the distributor cap next, but I am beginning to wonder as I listen to the splashy idle at the tailpipe if there is a lean running problem. This car has an EGR system; I had never worked on a 700-900 turbo with EGR. No fault codes are set. Any ideas?