now a misfire

[ian r thomas]

Hi to you all

You might remember me i was the one a few weeks back who's 460 had a irattic tickover which we seem to have solved, well its done it once since

But now its developed a misfire between 2-3 thousand rev's, the car pulls and excellerats ok but when its constant somewhere between 2-3revs it missfires, its like a plug not working ok, All plugs are new, new plug leads, and new distributer cap and new that plastic thingy arm, had a mechanic look at it and he said it could be a valve sticking and to use some redex it could come right again, and his parting words were well its an old car you can't expect it to run like new

Well its the 2litre engine its got 103.000 miles on the clock and as far as i can see as been serviced on a regular basis, i thought it would be just run in for a Volvo

Just one more thing when its first started on a morning for the 1st few mins it sounds a bit knocky but it soon goes and then it sounds as sweet as a nut

Any help would be great as i can't aford to spend much more on it i don't think its worth it

Thanks
Ian

[Daniel M]

The knocking noise on the 2.0 is quite common from cold...i think it's something to do with the spacers between cam's, but not 100%. It shouldn't be a problem though...

With regards to misfiring-plugs gapped correctly? New leads is a good thing-just check the king HT lead going to the centre of the dizzy cap is on properly, and at the coil end too. This is often easily overlooked. Also, make sure the the rubber shoulders on the leads aren't bent over or anything when they go back on the plugs-sometimes they can feel pushed home but aren't (not being patronising, just woth looking at).

If none of those work, maybe a replacement coil? If it's doing it under load, it means that it's not firing on all cylinders so something isn't getting the spark... Another check is to hold the lead slightly away from the plug with the engine running-give it a blip on the throttle and see if you can physically see a spark. Do it on all cylinders-if they appear ok, then get somebody to rev the car to the 2-3k range and see if it does it then... Be prepared for a little shock though-it doesn't hurt!

Other than those i'm out of ideas...

[ian r thomas]

Daniel M

Thanks for your suggestions, funny thing is that it doesnt misfire under load
it does it on the flat when the engine is cruising or when going down a slight decline, if it misses and you put your foot down it pulls away no probs

I still have a gut feeling its something electrical don't no what just this gut feeling!

As for this knocking from starting when cold it also makes a squeaking noise a bit like a alternator makes some times, so i sprayed it with wb40 but on listening close to the engine it was comming from there, could this be the valve sticking

To be honest iam a bit issed of with it so your help would be great

Thanks
Ian