Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[prbw]

I have just started suffering an intermittent misfire on my '02 Omega 2.6 auto.  First time was a few weeks ago, at cruising speed on a trailing throttle the engine misfired for about 5 - 10 secs, after which the emissions warning light flashed a few times, then all returned to normal.  Second time, again on a trailing throttle, while towing a van, similar 10 sec or so misfire, followed by flashing warning light, but this time the light stayed on.  Pulled in, stopped and re-started the engine, light went out and no sign of a misfire.  150 miles later in the same journey, the misfire returned, but this time it persisted, most noticeably at low rpm (2500 or so), and accompanied by the emissions warning light.  This time I kept going to my home, with a misfire all the way, for 1/2 hr or so, but once home, switching off then restarting the engine cleared the problem.  Suspecting oil in the plug wells, I pulled the offside coil pack and plugs - all clear and plugs good.  Despite the spaghetti covering the nearside coil pack, I got it lifted enough to check for oil and to remove the front plug - plug was clean, but all 3 plug wells appeared to have had coolant in them at some time, to judge from the residue, but were otherwise clean and were dry.  The car has not lost any coolant while I have owned it (35000 miles), so I assume the residue was from an old problem.  I have since done over 400 miles with no recurrence of the misfire.  So - I'm stumped, but the prospect of the problem returning at an awkward moment doesn't make for relaxed driving!  Have any of you experts out there got any ideas what the problem might be and where to go from here?

[Martin_1962]

Sound like plugs or coil packs.

There are some decent coil packs on Ebay

a-zparts4u they are a online shop for a real motor factors, funny packaging but look like genuine Bosch

[Big_Roger]

Hi,
This sounds uncannily like the problem I had.

Mine turned out to be coil pack 1-3-5 faulty.
Got mine from Vauxparts. Bosch for about £80.00
Do the pedal trick to see if any stored codes.

Regards
Roger

[joshwyatt]

I think your first port of call is to try the pedal trick, see what codes you get, you'll get 0300, and I suspect either 0302, 0304, 0306 or all of them.
1-3-5 bank or 2-4-6 coil pack may be at fault.
Cheapest thing to do first is to replace the plugs, if the missfire persists then I suggest a replcament coil pack is needed.
Check the scuttle above the 2-4-6 coil pack for any leaks, I've had this before...water leaks from the scuttle and permeates into the 2-4-6 bank killing the coil pack.
So, three steps - 1) pedal test 2) whichever cylinder it suggests is at fault replace plugs, be an ideal opportunity to do all 6 really 3) if no better then it's going to be the coil pack at fault. The lack of any other symptons means it's unlikely to be much else.

[prbw]

Many thanks for that.  As you suggested, 0300, 0302 and 0304 fault codes came up, so at least I know where to look.  Seems that I've got a job on over the Bank Holiday!  As a matter of interest, with the problem not occurring at the moment, how do I clear the fault codes?

[RobG]

Codes need clearing with a half decent code reader, but in saying that if the fault is rectified codes will clear in time. As Josh says, you could try new plugs but my guess would be coilpack breaking down as you`re misfiring on two cylinders