Constantly having to Change Spark Plugs

[Guff100]

I have a 1997 Ford Aerostar, with 225,000 km. The spark plugs have to be replaced every 6 months. Currently the #2, 3 and 5 are misfiring. I've changed the wires and put Ford plugs in 6 months ago. Why is this constantly happening?

[RahX]

what do the plugs look like when you pull em out?

[truckdude239]

coil or distbutor? if its coilpacks replace the coils

[Guff100]

I replaced the plugs today. They looked fine.

[occupant]

My van goes through a set every year, but I drive about a thousand miles a week. It never misfires, but it does lose power, when it gets to a point that I can't accelerate past 55-60, I change the plugs and set the timing.

But for a misfire, I'd guess your cap and rotor need changing. Cap and rotor are easy to change, parts are cheap, I'd start there. Especially if your plugs look good when they're pulled.

[Guff100]

Originally Posted by occupant

My van goes through a set every year, but I drive about a thousand miles a week. It never misfires, but it does lose power, when it gets to a point that I can't accelerate past 55-60, I change the plugs and set the timing.

But for a misfire, I'd guess your cap and rotor need changing. Cap and rotor are easy to change, parts are cheap, I'd start there. Especially if your plugs look good when they're pulled.

After I replaced the plugs, the van is again working fine. But like in the past, I am sure in 6 months the van will run rough, the engine light will come on again, and after putting the computer on, it will indicate the spark plugs. Do you still think changing the cap and rotor will help?

[occupant]

Originally Posted by Guff100

After I replaced the plugs, the van is again working fine. But like in the past, I am sure in 6 months the van will run rough, the engine light will come on again, and after putting the computer on, it will indicate the spark plugs. Do you still think changing the cap and rotor will help?

I think so. The computer can only tell that there is something missing between the plug and the distributor. It could be the plug itself (they are fine) the wires (you replaced those) the cap, or the rotor. So I'd try those two pieces next, especially since it's so easy to get to and the parts are cheap and probably need replacing anyway. Look for cracks and carbon tracks in the old cap and for wear on the rotor tip and the contact points in the cap itself. If they're clean and look good, then I'm out of ideas.