intermitent running problems! help!!

[matt_elan]

Hi guys, ive got a problem that I thought was just something wet because of me jetwashin but im not sure now. Basically it mis fires under load. it seems 2 go away, then come bak! one day fine, (or 1 hour) and the next, misfiring! ive changed the plugs, cleaned loads of connections and still it returns! dont no if it cud make a difference but my speedo cable is shot and waitin on a new 1, I know there is a speed sensor, cud this play a part? cud it b the leads? tho i wud av thought if it was leads it wud either work or not!? Coil pack? hope someones got some ideas cos its doin my head in!!!

cheers
matt

[NIL8379]

I'd put my money on a duff lead.
I had a terrible intermittent fault on an Astra, turned out 2b a lead in the end. Would run without a misfire for weeks and then come and go. I should have changed the leads b4 I changed the electronic ignition module at £75.00.
Cured the fault with a 25p lead from an oddments bin at a local spares shop..............DOH!!!!!

When I dissected the faulty lead it was corrosion between the metal cap and the inner carbon fibres..........very irritating.

My philosophy is to change the cheap stuff first now.

[Doug]

agree with good advice above

leads suspect
less likely coil is suspect
CAS - Hall Sensor is suspect

check the leads and replace the speedo cable, see if any check engine lights are showing up after that . . .

[JLSELAN]

Also agree with advice so far.
A way to evaluate the soundness of the HV leads is to check under the hood (bonnet) at night as you change engine speeds to see if there is any electrical arcing to ground (earth) from the leads. You may be amazed by the light show you see .
Cheers, Joel

[Doc Fizzix]

Just for fun, not likley but I spent sever weeks replacing plug wires, fuel regulator and fuel pump, sensors, and the coil only to find that my problem was with the injectors. Car ran like it was missing and I thought it was an ignition problem. The last place I was looking was bad injectors.

My two cents worth

[matt_elan]

Ive ordered some magnacor leads but will take a goog few days to arrive, so i ll have 2 wait n c!! i ll let ya no the out come.

[piston_broke]

have you checked the fault codes
and
check as many of the earths as you can find-I had a problem which was an earth off by the injectors
good hunting
cheers
d

[matt_elan]

are there any main earth points I shud b checking?

[Ade]

Hi.
we seem to have the same fault. I have also tried new plugs and have assumed my plug leads are o.k because they were new with a new engine, I know foolish, they could still be faulty. I am going to try a new fuel filter and then work my way through all possibles. I have checked for fault codes, no faults shown. I will let you know if I fix it, but you know the problem, just when you think its fixed, it returns. Steve from SJ sports cars said these are the most difficult faults to find if there are no codes.

Best of luck
Ade.

[matt_elan]

new leads and that cured it!! cheers guys!