I did a tune up to my Volvo 240 DL Sedan 1990 and this was the first tune up i ever did in life. I used Bosch Super+4 pregaped spark plugs, and replaced the rotor cap and wires with brand new Bosch ones. I did every wire and plug one at a time to make sure I did not mess up the fireing order. The only thing I didn't do was clean the area before putting the new spark plugs in, but I was real carefull to try and not get them dirty while placing them in. For some reason...and maybe it's just me...but it feels like the engine runs not as smoothly. Is this possible from the tune up I did? Or could it be just bad gas or me being paronoid that I didn't do something right?

 

did you clean around the rotor area inside the cap? There could be oil still in there.
Also did you gap the plugs? They need to be 28-30mm. If that was the first tune up ever, Let LH learn the tune. drive it around a few miles on the highway and on the street.

Wait for the experts to get on.

 

the spark plugs were already pre-gapped(Bosch Super +4). the instructions said not to gap them. i placed a new rotor cap on there, but i didn't see any oil inside the rotor itself. it was really clean in the rotor.

 

I don't know if the 4 cyl is as tempermental, but my 6cyl 960 ran like crap when I put the Bosch +4's in it. Idled so-so, and had a very noticeable miss on the highway. I replaced the bosch with Volvo plugs and it ran like new. So if you have a place where you can get your hands on some volvo plugs I would get some and see if it solves your problem.

 

In my opinon, the Busch Super +4 are crap. Throw ina cheap set of NGK BRP7ES.

 

Good plugs there