need help!!!

Hi i'm a new user. I have a question. I have a 740 volvo 1990 and when I drive the tach will jump up and down and the check engine light will flash also the car will stall for no reason. any help would be great thanks.

Well Brad this could be alot of things, first always check the obvious. Start by making sure all of your harness connections are tight at the computer, which is in the passengers kick. If the computer has been replaced the connector might not be properly clicked in. Then also check your coil, make sure all the connectors are tight there as well. Then, check the ignition amplifier it is located on the drivers side under the hood behind the airbox mounted against the the fender. Volvo does use great connectors on these things but hey you never know. Any loose connections on these modules would give you these symptoms. Could also be a distributor problem but thats a another story. Yikes! good luck bro!

Does your tach drop befour the engine it's self drops? does it usholy happen once the car is warmed up? normaly when u start the car can you see the tach twitch when it's turning over?
okay if you can see the tach move when you are starting the car normaly and if the car dies on you and you go to restart it and the tach does Not twitch that i would start looking at the ignition amp aka the hall affect sensor. some are located on the flywheel as i suspect yours is, others are located under the distributer.

okay next question... does your tach seem to make the engine cut off?
meening, is it like the engine is fallowing the tach when it falls? it dropes fater than the engine actualy cut's out? this would allso seem to be an ignition amp problem. i had the same problems with my car at one point (a 760) i dont know if i will recheck this poast so if you have more questions please E mail me, then i will be shure to poast any information i can along with questions and such

hope i helped, Gary