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Jerry, Master Mechanic
Category: Mazda
Satisfied Customers: 17218
Experience:  ASE Master certified, 30 years experience. Auto troubleshooting, electrical , ABS, SRS, EFI system
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2 ford falcon: ignition coil pack and the spark plugs..running rough

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Have a 2001 mpv. Three weeks ago I replaced the ignition coil pack and the spark plugs because the car was running rough/spluttering pulling away from lights and up hills. I replaced it with what I was told is the sme as what is in an au 2 ford falcon. When I fitted it the lead numbers weren,t the same as the original. I put the leads on the coil pack as what was written on the new coil with corresponding lead and it wouldn't start. I then put the ignition leads on as they were on the original and ran properly. It was going well until today where it is really spluttering under load worse than before I replaced coil and plugs. I'm not sure whether it's a fuel or electrical stemmed problem. The car has done nearly 180000 kms.

Hello and welcome to Just, Super mechanic here. About your vehicle.

I have tried to transfer it to the Mazda category, as per JA rules. As soon as the moderators get it there, I should be able to help you, or someone will, thanks

Customer: replied 6 years ago.
OK thanks for letting me know that.

You will want to check the fuel pressure and make sure that it is not low.

Pressure Fuel System Pressure
Fuel line pressure 0.38-0.42 mpa (55-61 psi)
Fuel hold pressure 0.176 mpa (25.5 psi)

Also, the fuel filter, could be restricting the flow of fuel, but that is in the tank.

Also take a fuel sample to see if any water, (or other liquid) may be mixed with the fuel.

Customer: replied 6 years ago.
I haven't access to guages to check the fuel pressure. When driving if i put the car in a lower gear and keep the revs up it seems to run okay. But as soon as i have to slow down for trattic lights and take of again the spluttering is there. Can a faulty PCV valve do that. Or even a weak ignition lead. I haven't replaced them.
The PCV won't do that but the ignition leads can. One good way that I have found to test them without a scope is by wetting them with a spray bottle of water and then see if the engine has a really bad miss. Or they could be checked with an ohm meter.




  1. Measure the resistance of the high-tension leads using an ohmmeter.
    • If not as specified, replace the high-tension leads.

I noticed that you have not replied, or accepted, did you need any more on it? Please don’t forget to hit the accept button though, that is the only way we get paid, thanks

Customer: replied 6 years ago.
Graham is still working on the car. He will get back to you soon as he can. thanks in advance da wifey... Judy
Okay, thanks. I'm getting married in about 2 weeks to a Judy, (nice name, lol)
Jerry and 2 other Mazda Specialists are ready to help you
Customer: replied 6 years ago.
I checked the leads with an ohm meter and they were all in spec. I'm wondering if it can be an injector or maybe the new coil has failed. I tested it and one of the secondary tests was a bit lower reading than the others but still in spec. Grasping at straws at the moment with many sensors talking to the PCM hard to know. I plan on taking it to get hooked up to a scanner to retrieve codes.
Yes, if there are any codes that might help a lot.
Customer: replied 6 years ago.
I'll keep you informed when i know what codes are active. Hope there are active ones for that will help a great deal.
Thanks, I'll be here.
Customer: replied 6 years ago.
Took the car to the Auto Centre and hooked the car up to a scanner. No Codes to retrieve. Mechanic suggested clean the mass airflow sensor, but that made no difference. We talked between us and thought it wasn't injectors. I went to the place where I got the new coil from and expressed my concerns that the coil had failed they asked if I had changed the leads, I said I hadn't but I tested them with ohm meter and were ok but if failing on the load I wasn't sure. I spent money on a new set of leads which made no difference. We back to shop and was given another coil, put it in and went for a drive around the block and problem fixed.
Wow, so it was a defect with the coil? That happens, (just not a lot) but glad that you got it fixed. Thank you for using JA and come again, anytime. Please disregard any reminders that you might get about it. Thanks again.