S40 2.0L 16v misfire/missing/lost the plot?

[donmarrese]

Hi all Last week, I decided to treat my Volvo to a new set of plugs. 4th set this year as I average 30K miles a year...M11 commuter. I bought the car a year ago with 75K on clock, full service history, lady owner etc, P reg in v.good nick. No problems untill now. A day after changing plugs I get a rough idle like it's a 3 cylinder...so I locate the cylinder, being No. 3

Pulled no. 3 spark lead out, no change
release injector electrical cable from no. 3 no change


1. New plugs again....no change.
2. New leads....no change
3. New coil pack...no change
4. remove injector cable from no. 3...no change
5. Spend bucket loads on different injector cleaner, making sure there's not a lot in the tank...followed by an Italian Tuneup....no change
6. Go Lea Valley breakers and change injector for a bone fide one....no change.

Acceleration and general cruising is OK, but at lower revs, it's a different story...

I'veyet to do a compression test, and swap injectors round...but I think I've got a dud valve.....and I've also got a new sound comming from the engine bay, like a metallic tick, really evident when crouching by the front offside wheel....any Idea's?

Never had these probs with VW, and I was beginning to think volvo where better.....

[stevo48]

Sounds very much like a valve problem, had you been driving the car hard prior to the misfire?
I've had the same symptoms myself on a car I owned many years ago, turned out to be a burnt valve, funnily enough that car was a one lady owner prior to me buying it as well.

[donmarrese]

Hi Stevo...thanks for your reply.....errr yep, that morning I was doing 80-90 down the M11for a constant 30 mins, no more than 4k rpm...surely the engine can cope with that? I've never gone past the 4k mark, unless the old lady did?

[stevo48]

Get a compression test done mate that will determine whether or not it is a valve.