Volvo "bucks" while driving

My 240 has started acting strange. It hesitates while driving after it has
been driven awhile. I tend to think it is the clutch slipping, but it seems to
drive ok then all of the sudden it "bucks". ( best term I can think of but it
feels like the cars is going to throw you out of the seat) Generally when the
clutch starts to go , it goes gradually and never drives normal again. This is
strange because sometimes its drives OK and sometimes it "bucks. Engine has
new plugs, wires, air filter and a new fuel pump. Is it the clutch or
something else ? ideas ?

 

What year is it? Also is this a US spec car, or elsewhere? Makes a
difference as to what engine and fuel system it has.

First thing I would check is the fuel pump relay, the solder joints in it
usually crack when they get old.

 

If it's the clutch it should roll smoothly when you press the pedal in?

 

First thing I would check is the fuel pump relay, the solder joints in it

At this point I'm pretty sure it is an engine stalling problem under load. It
won't stall while idling, but at higher RPM it will and will driving it will.
Maybe leaning out due to fuel pressure or ignition advance is not set correctly
?

Fuel pump relays are both new, new fuel pump and filter, tank pump works fine,
new wires and plugs, new engine harness and ignition harness. New air filter.
So the only thing I can think of is O2 sensor, Air Mass meter,
fuel regulator, injectors and possibly catalyst or even distributor ? Any
other ideas or places to look ? Thanks !

 

Hi "Neoisthe 1",

Regarding your Air Mass Meter, try this: (It seems to have worked for a
similar problem with our '93 245.)

1. Depress the wire clip on the AMM.
2. Pull out the plug.
3. Coat the plug contacts and the AMM contacts with DIALECTRIC GREASE.
4. Push the plug in and out about ten times.
5. Test drive!

Good Luck.
Andy I.



| At this point I'm pretty sure it is an engine stalling problem under load.
It
| won't stall while idling, but at higher RPM it will and will driving it
will.
| Maybe leaning out due to fuel pressure or ignition advance is not set
correctly
| ?
|
| Fuel pump relays are both new, new fuel pump and filter, tank pump works
fine,
| new wires and plugs, new engine harness and ignition harness. New air
filter.
| So the only thing I can think of is O2 sensor, Air Mass meter,
| fuel regulator, injectors and possibly catalyst or even distributor ?
Any
| other ideas or places to look ? Thanks !
|
|

 

Silly to think but what about ignition coil? is it getting more
frequent, and/or cold weather related?

Good Luck