Got an MX5 today

[tuscan_thunder]

Hi all,

Got our MX5 1.8i Mk1 today. 96Nreg, 17k miles (!) one owner, FSH. Non-power steering model.

Excellent car, really pleased with it (so's the better half, it's her's really).

However: 2miles after picking it up, it felt like it was 'missing' like it was dropping onto three cylinders. I pushed on all the plug leads (they seemed secure anyway) and drove it again, this time a wee bit longer a run. The problem seems to have gone away.

Could it just be the cold start? It is snowing here today and the car's not moved much in the past week. Put in some fresh fuel too just in case it had a dose of stale fuel.

Any suggestions?

Thanks

[tuscan_thunder]

Well,

It did it again, so I took it back to the garage.

The car cleaner guy had steam cleaned the engine and had soaked the plug leads. Two minutes work with the air line and problem solved.

The car is now (touch wood) back to full health and is an absolute delight.

[tuttle]

cool! have loadsa fun in it.

[cptsideways]

Check the plug lead holes for water It'll be damp in there

[mxdi]

Mine ran slow for a good few weeks, I think it had been sat stationaary for too long

[juzzyp]

Have a Google for MX5 Parts which also have alot of stuff for the MX5 and to make your 5 go even faster, Google Performance 5 or Tracktec.

A good set of leads and plugs is essential for these cars.

[franv8]

There are a number of possible causes for rough running, (failed ignitors (coils), problem with the cam position sensor etc.) BUT the biggest and most likely the cause of this is the ignition leads.

These cars are (for some reason) really hard on ignition leads. It is normal for a standard set to only last between 20 and 40,000 miles. Sadly, you can't test the leads the usual way of checking the resistance along the lead - it will appear fine. I think it's breakdown of the insulation, and this is relatively invisible.

The solution is some new leads. MAzda will want £60 for these, and if anything like the dealer I use in Peterborough, won't have them in stock. mx5parts do about 4 options for leads, pattern set for £25 up to the race version of the Magnecor leads at £60. Best do the plugs at the same time for the sake of £8. Service from these people is excellent, virtually always next day delivery.

My car suddenly went poor pulling onto a roundabout (v sudden deterioration), replaced the leads and all was fine. Incidentally, changing the used plugs (about 20,000 miles on them too)to the slightly longer nose variants yielded and extra 6hp and changing the standard air filter to a K&N gave an extra 2-3hp.

Hope this helps, incidentally, the symptoms of lead failure are much more apparent at lower revs/idle, when the first set of leads went in the car I have, it ran fine but was rough below 2000 rpm. Oh- and don't try and find the dodgy lead by disconnecting them as its running, since this tends to stop 2 cylinders firing due to the way the ignition is configured.