- Hello all. I hope someone can help me out with this. When i start the car up from cold she starts straight away. However if you blip the throttle she misfires. As the car gets warmer the engine misfires more and has even stalled. When driving the car the misfire is rather bad. I've changed all the plugs (the old ones were less than a year old) but she still misses.Took her to the local garage who checked for fault codes but nothing showed up. The mechanics were at a loss as to what the problem is. They said i might be the coil and to get as second hand one off a well know auction site. They said that it was a single coil but i'm pretty sure that its a coil pack i need, although the mechanics weren't sure if this was the problem anyway. Would she start first time if the coil was faulty? Any ideas as to what the problem might be would be greatly appreciated. The car is a 1.6. Thanks
sounds like the coil pack, but it could be fuel, if you have some one local who knows their round a 5 take it to them.
where are you based
Hi. I’m about 6 miles north of melton mowbray. i will have a look on ebay to souce a coil pack.
Give Sam Goodwins at Nuneaton a call (02476 353 909 ) - they are very helpful
Sounds like the Idle Air Valve to me.
Hi, have you changed plug leads,if not it’s a common misfire culprit.
Hi. The garage checked the leads and said that they were ok. They could not check the coil for some reason
Thank you.I will have a look at that as well
HT Leads often “look ok” but they dont last long on an MX5, Two years is common, so you should get a set to try,even if it isnt the problem they wont go to waste. Not too expensive for standard leads so well worth a go before anything else. Mine was sorted in this way when i first got the car. Good Luck
My leads are original at 10 years old (108000 miles) - still fine.
In the end, an HT lead is a wire…nothing more. If they checked the resistances and the insulation is intact, then they’re good…there’s no point replacing a part for no reason. They probably don’t have a mega-ohm resistance meter to check the coil breakdown resistance - it’s a fairly expensive bit of kit. Case breakdown is about the least likely fault with a coil pack, so I wouldn’t worry about that.
My money is still on Idle Air Valve (or ISC valve possibly)
My money’s on leads…and they’re much cheaper than a coil pack
I would bet on the coil pack - often fine on startup but running problems when warm or under load.
Idle air valve problems often manifest themselves on cold startup with high idle and go away when engine warms up