Yellow label 556 is failure prone just like the pink label 561. A white label 933 or 946 is the upgraded one for 2.4 with EGR. I have a couple spares from the local pick and pull. Send me an email if you want.

I've had a similar problem a few times and for me it's usually been fuel: clogged filter, water in tank, crimped line, failing pump. I had a new pump fail 3 years ago.

I've also had a problem like that caused by broken wire and/ or bad ground.
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240s: 2 drivers and some parts cars

Here you go. From Yama's earlier post. No guarantee this is the problem though. Yellow label is bad as indicated. Maybe someone can loan you a white label one and you can switch for awhile to test the ECU (computer).

http://www.brickboard.com/RWD/volvo/1422080/220/240/260/280/1990_240_dl_problem.html
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95 855 GLT Sportwagon, 93 854 GLT (for sale), 90 244 DL 300k :)

I bet the crank position sensor has cracked shielding, before spending much more wrap it w/ aluminum heat tape.You can get a roll in a home depot for $5,they use it to wrap leaking exhausts on oil burners.
&then you may have a wire that is cracked on the in tank,,pump..that sound s like my 245 3 yrs ago,,,many small cheap fixes,,that happen because the cars last toooo long..chk back &or use the search engine here,You'll find easy cheap answers.