1. Home
  2. Mercedes Autos and SUVs
  3. mis firing at low revs

mis firing at low revs

My C180, UK, has been fine for a year or so, its 5 years old, and next service due in 3k miles. Its started backfiring a little and missing, as if its only firing on 3 cylinders at low revs, between 400 and 1000 rpm. Once its got going its fine again, unless I'm in 4th gear or so, and revs are down at 2000 and I put my foot down a little too hard, and its misfiring again. Any ideas ? I thought I'd cahnge the plugs, as I have always done that sort of thing myself before, but, had a look, and I cant find them, I guess they are covered in somewhere.

toad, Worcester UK

Reply to
toad
Loading thread data ...

To lean an air / fuel ratio. The fact that it runs poorly at idle and low rpm suggests a vacuum leak - perhaps from a split or disconnected vacuum hose or loose intake manifold.

Reply to
T.G. Lambach

thanks for the reply. Any idea how to fix it? or is it a garage job.

toad

Reply to
toad

I HAVE OWNED 12 MERCEDES BUT HAVE KEPT A 86 420 SEL THAT HAS THE SAME PROBLEM PERIODICALLY.PART OF THE PROBLEM IS WITH YOUR GAS(WATER)--PUT A CAN OF DRY GAS IN TANK--RARELY A FOULING PLUG,BUT HAS BEEN AN INJECTOR--HAVE LOCAL SHOP SCOPE THE ENGINE---CAR NEEDS TO BE RUN MORE FREQUENTLY--SPKSR

Reply to
Stephen Kelner

I dont thiink it is the gas, ( petrol here in the UK ) , I run about 1000 miles a month, and fill to the top about twice a month.

I'll get a garage to check it out. many thanks, great ng.

toad

Reply to
toad

Check the spark plug... usually it is a bad spark plug wire causing misfire... but can also be your distributor... check them all.

Reply to
Tiger

Had a look in there, but cant find the plugs, are they hidden under some panel somewhere?

toad

Reply to
toad

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.