MY COOPER IS A 03 jcw and at about 70 MPH my engine feels like it has a miss once in a while. what can it be

Thanks REDDROCKET

 

Have you checked the spark plugs? I would start there.

 

Check plugs,wires and coil. Try some seafoam in gas or techron in gas this may help with the miss.

 

thanks i was thinking about getting the msd coil with good wires and plugs , have you herd any good with the msd coil......... Thanks G

 

thanks i do use the good gas chev or shell have you herd any good on the msd coil i am thinking about msd good wires and plugs......... Thanks G

 

I have the screaming deamon coil on my 05 JCW with 8mm magnacor wires. they seem to work well. People say the stock coil is very good and don't need to get aftermarket one. Also have been hearing that Brisk plugs make a big change in performance of engine. RMW has them for sale.

 

Thanks ill check out does the demon make a differnce....

 

An 03 with orgional wires might be due....the coil unless defective should not make a differance. IMO, do the wires....any quality set will do, plugs are due on a JCW at each service....so they might be the culprit, but a miss should cause a check eng light....safe to say you are useing 91 octane or better too right.

 

thanks for the info i changed the plugs sh -- plugs i got where 14 bucks each but its ok the car runs goood ..... i do use 91 octane. im going to order msd wires tonight ....... again Thanks G

 

My regular 2002 Cooper was missing/hesitating a little at 70+ (60K miles, original plugs, wires, etc). I pulled the plug wires at the coil and two of them were slightly corroded.
Cleaned them up and it has been much better..

 

rpm and load is what matters. Anyway, I had screamin deamon and it made little or no difference. MSD looks better but I'd put it in the same category...

An occational miss will throw code P0300 (random misfire). It will be pending at first, and if it happens often enough, it will set the check engine light.

Start at plugs, then wires... A bad coil normally shows up at higher engine loads, but then again, anything is possible.

Matt

 

i still have this miss after changing the wires and plugs and no engine light could it be fuel pump