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MX5 intermittant misfire - SalEv
In the three years we have owned our 2000 W MX5 1.8 Icon, it has been a pleasure to drive. Unfortunately, over the past 18 months the car occasionally develops a severe misfire when started from cold. When the car is started, there is a strong smell of petrol, as if the engine has flooded. If we try to drive it, there is no power. The only solution seems to be to switch off, wait five minutes and restart the engine, at which time it runs normally.

There appears to be no pattern to the problem. It occurs during any weather conditions and may happen twice in a week or not happen for several weeks or even months.

Our local garage, with the help of the local Mazda franchise, can offer no solution as it has never happened whilst the car is at the garage. Diagnostic testing has shown no faults. The car is serviced according to the manufacturer's requirements and has covered 58,000 miles.

New plugs, filters and an engine flush have not solved the problem. Any ideas?
MX5 intermittant misfire - bell boy
do you touch the throttle pedal while starting it?
MX5 intermittant misfire - Ian D
Try new HT leads...
MX5 intermittant misfire - Aprilia
Sounds like its overfuelling for some reason. I would replace the coolant temp sensor (the one for the ECU, not the one for the gauge) they are not expensive, and carefully check the wiring and connector.
AS mentioned above, also consider a new set of HT leads - they are a bit of weak spot on the MX5.
MX5 intermittant misfire - mjm
My son had the same thing on his. As Ian D said, new HT leads cured it. 1998 car with about 35k on the clock. I think they start to go at about that milage so yours have lasted well.
MX5 intermittant misfire - Peter D
Had exactly that. If it fires up wronly it stays wrong. Stop and disconnect the lead to the top of the dual coil pack and reseat it fire it up. If it cures it several times then the coil pack has failed. Last one replaced under extended 3rd party warrantee. Regards Peter
MX5 intermittant misfire - martint123
HT leads are a common fix for MX5 misfiring as stated. The coil pack is also very vulnerable to damage if the ignition is left on without the engine running on later cars. And they're not cheap AIUI.
MX5 intermittant misfire - mark999
HT leads are a first port of call on the mx5. Try www.mx5ocforum.co.uk for loads of good advice

MX5 intermittant misfire - Ian D

Any update to this one? It is good to see what the outcome was!


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