My 960 has recently started idling rough at startup and has poor acceleration and rough running until completely warmed up. Feels like it's running on 5 cylinders. I'll be running rough on the highway... smooths out... rough.. smooth... then just smooth. Sounds like a noisy lifter when it's rough, but being 24 valves I wouldn't think one would have such an impact on performance. 210,00 miles, Ignition Control Module already replaced, one coil pack replaced (guessed misdiagnosis, I suspect). My mechanic is still leaning toward electrical, but I think he's barking up the wrong tree. Any ideas? Feel free to ask me for more background. Thank you!

 

are you getting any codes? have you checked all the plugs?

 

I don't have a code reader unfortunately. New plus about a month ago.

 

i would start by either buying a cheap one, or finding someone close by to read the codes....if it is pre 1996 it is an obd1 and then the codes can be read without a code reader.

 

OK, cool. Yeah, it's 1994. I went with synthetic on my last oil change. Could that have been a mistake?

 

changing oil to synthetic won't cause the car to run differently. I'd start by checking vacuum lines, the idle air valve, the intake boots. I'd also replace wires/rotor/cap as well to baseline the ignition.

 

OK, I guess nobody's picking up what I'm putting down. Kind of hard to replace anything on the distributor when it doesn't have one. The engine is making a mechanical noise like a stuck lifter when it isn't completely warmed up. Once it's hot, it runs smooth and that noise goes away. Now that temperatures are cooling, it takes longer to reach that temp. Thanks anyway! I'll keep guessing.

 

the book says that the lifters will tick sometimes up to 15 mins when warming up..... or if the car has sat a while. did you try to pull the codes? guessing on these cars get expensive and fast.

 

Boy, is my face red. I finally noticed the oil pressure idiot light isn't coming on when I start the car. The valve train had been getting noisy. Could it be? Yup. It has a capacity of 6 quarts. Took 4 to read on the stick. How it didn't explode before now (I do 70 on the highway to and from work) I have no idea. Volvo engines must be bulletproof!