'84 240 vibration at idle PLEASE HELP!!!

I have a 1984 240 gl with 115,000 mi. on it, I have had a horrific
time trying to diagnosis this problem. The engine has a "rough idle
and shake" at the end of its cycle, there is also a vibration that
steadily increase up to about 1500 rpm. I have a laundry list of parts
and services that have been done, mostly by the dealer to no avail.
The dealer has been no help, and they have told me that the car is
just "old". If anyone has any ideas or experience with this please
HELP!

 

The fuel window on those cars is very narrow, which means that the throttle
body must be clean and set up properly. Go to your local Volvo dealer, walk
into the shop and find a tech who does side work. Doing this pays 1 hour,
but can be done in 15 minutes and makes an amazing difference in how the car
runs.

 

I have heard that the motor mounts on 240 's are notorious for breaking. Mine
had two broken ones but the idle was still normal.
Rojo

 

I'd guess a bad motor and/or tranny mount. Mine went at about 125K. Not an
expensive or difficult fix.

-jeff

 

I have a 1984 240 gl with 115,000 mi. on it, I have had a horrific

It could be the motor or tranny mounts, but you'd think they would have caught
that. On my '92, I had this thing happend where the exhaust was hitting but
only when the engine was loaded up, and it created a vibration that was very
difficult to diagnose...

-jeff

 

there is also a vibration that steadily increase >up to about 1500 rpm
Another thought I have. I had a rough idle and it turned out to be corroded
spark plug wires (just two). I would recomend checking the spark wires
especially if they are old. Mine weren't but in washing the engine, months ago,
water must have gotten inside the caps and corroded them. The sign was a white
powder packing inside the caps. I cleaned them, no difference, replaced them
and the car idles and runs fine.
Best of luck, Rojo

 

Turns out it was the throttle plate and throttle switch, after a lot
of complaining, the dealer did this for free! They also replaced the
coolant temp sensor, there is still a bit of a vibration, so I need to
check out the motor mounts, thanks for all the help.