powellst

I have some hesitation in my 2002 3.8V6 when maintaining a steady speed or starting to climb a hill. It also does it if needed to quickly accelarate. I've bene told that there there may be a problem with the ignition coil/s. there is no SES light, and no code being given off to read from a scanner. This is where the confusion sets in. I was told that there is an ignition coil that sits on top of every spark plug and one of these may be going bad. However, from my looking at parts...there seems to be just a square looking "ignition pack" that connects to the plug wires and is mounted on top of the engine, to one side of the throttle body.

It seems the V8's have the individualignition coils on every plug/cyclinder. Am I wrong ?

Derf00

Could be the spark plugs wires themselves (as always was the issue on my 00 V6). Especially on the passenger side where aftermarkets often come in contact with the exhaust manifold.

Coils rarely go out on the V6 (99-2004) because they are remote mounted (away from the heat).

Under loads, the coil sends a larger spark to the plug, this larger spark could arc out of a bad boot and ground directly to the engine instead of through the plug like its supposed to, thus the feeling of hesitation and lack of power when you step on it.

Order a set of Motorcraft wires from RockAuto since the motorcraft ones will have the properly angled boots. Most aftermarket have straight boots that suck. Replace them and your problem will most likely be solved.

petrock

I don't know what coil packs the V8's use since I've never worked on one. But V6's coil pack is a single rectangular box with 6 plugs coming out of it that the spark plug wires connect to. If you end up replacing it, get a motorcraft one instead of some aftermarket one. Rockauto.com sells the motorcraft coils pretty cheap.

With that said, I agree with Derf00 that the problem may not be the coil pack itself. It could be the coil pack, one or more of the spark plugs, one or more of the spark plug wires or any combination of these. Remove the coil pack and give it a good visual inspection for any cracks or burn marks. If you find any, then replace the coil pack. Then inspect the spark plug wires for cracks, wear marks or other damage. If you find any, replace all of the wires. Then check the spark plugs to make sure that they are not damaged or fouled in any way (the white part of the plug could be cracked and arcing against the engine). If they are damaged, then replace all your spark plugs.

If all of that checks out, drive the car to a dark, well ventilated location and pop the hood. Then have a buddy rev the engine while you look in the engine bay. Look all around the engine bay for any flashes of light. The flash of light would be an arc. If you see any then that should indicate where the arc is occurring and causing your hesitation. Replace the part that is arcing. You want to be in a location with low ambient light around you so that you can see the arcs easier. So the darker the better.

Good luck...

powellst

Thanks for the replies...I'll think I'll be changing out the plugs/plugs wires and fuel filter soon and see how that works.

powellst

Changed out all the plugs and wires today with Autolite professional wires and NKG plugs. Apparently found the problem, as it runs much better. No hesitation or bucking under load. Getting on the interstate after the change, I was up to 75 by the end of the ramp before I knew it...much improved.

mustangmike09

Good deal.
And as to the comments, all years of these 3.8s are known for coil pack failure before spark plugs or wires. Very common. But never the first place you should look.

When Mine went out a couple months ago, my plugs only had 5 months of use...
So I pulled them, looked fine.
Then bought a new set of wires and coil pack. Wires didn't solve it but coil did. So I took the wires back.

Copper plugs are the best on these cars.
Id try and stock with Motorcraft for as much as possible when buying parts.

powellst

I was almost ready to press the order button on a new coil from rockauto.com a couple of days before switching out the plugs/wires, figuring I'd need it. But, as it turns out...I ended up saving a few bucks and not needing it right now. I had to wait a little longer to change them than I would have liked, because I didn't have the right extension or swivels.

Those OEM plugs looked pretty burnt up at 50,000 miles, too BTW.

daves2001

Hello everyone,
I wanted to share my issue and resolution with the forum. I get so much help from reading posts and need to pass on some information that may help someone else. My 2001 stock V6 (150k mi) started stumbling/missing/bucking under normal acceleration. Really significant loss of power making the whole car buck. It never died and never threw a cel code. If driving in town with minimal acceleration drove decent (even hard to tell it was not right). Idle was fine. I do my own regular maintenance and knew that, while the tune up parts could be suspect, all the normal items (plugs, wires, fuel filter, air filter, PCV, etc.) had been changed during my normal maintenance activities. I was really confused by the lack of an engine code. At least I assumed a mis-fire code cause it sure was missing. I struggled to decide if I had a fuel delivery issue or spark issue. After reading several posts I decided to replace the ignition coil. On this car it is one unit mounted high on the driver's side of the engine. Very easy to install (3 7mm bolts and one electrical connector) and was only about $70. I was very happy that was the problem. Runs perfect. Worth a try to replace if your symptoms are similar. Thanks to all for taking time to pass on the valuable information in these forums. Even us guys with stock daily drivers get lots of help here!!!

yiannisthegreek

^ +1 :-)

hurricane1091

I had the same hesitation. Was the coil pack. It's just one unit, not separate coils for each cylinder. Ended up fixing it for me. Plugs were brand new almost for me but bad plugs can cause it too.