Should I change my coil pack?

Ok heres the deal. Over about the past 2 years my explorer has been getting crappy gas milage (13mpg), and has also been knocking. Recently it has started hesitating. I just did the plug and wires today, we'll see how they work out. I also have a new fuel filter for it. Ive also re-torqued the intake, and it did good for awhile. Ive had to up the fuel to premium so it wouldnt knock. The car has 195,000 miles on it, with about 37,000 on the engine, and a few hundred on my manual tranny that just went south

Anyway, can I get some opinions? Maybe I should pick up a spark tester? When I pulled the plugs the chart in the haynes manual said the plugs looked normal/rich condition......

Thanks for the help guys.

Have you scanned for troublr codes yet? If not, I would recommend doing that next.

Good luck.....

I thought codes only came up when the check engine light was on. Ill have to run those tomorrow...

Normally a coil pack works two ways. Either it works or it dosen't. Pretty simple. Do you notice a mis-fire. I have seen a cracked post on the coil pack cause a mis-fire only when it rained. Might want to check how you drive the vehicle. If you romp and stomp on it then you will get bad mpg. Are your tires up to the correct tire pressure. Just some simple things to look at. Did you have a clean air filter?


Eric

Havent checked tire pressure...

I also need a clear definition of misfire. Its pretty much a severe hesitation that is incosistant. Some times I drive aggressive, but I tried easing up, and the needle seems to move as fast. I have a K&N....Its semi-clean.

Do you notice the engine running rough? Maybe shaking? These are some of the ways you can notice a mis-fire. You could have a leaking intake. Might want to try some carb cleaner and sprat it around the intake were it mounts to the lower intake and were the lower intake mounts to the block. Also could try to run a fuel pressure check, if it is low you will have a hesitaion.

Hope this helps.

Eric

It runs at 600, which seems a little mow to me. Sometime when I leave it just idling, it drop to 500, and shake, not violently though, for a few seconds.

Is there a way to test the coil with a multimeter?

Clean the MAF sensor (if equipped) yet ? Makes em knock, ping , and run like dog poop .

The MAF is practically new....

You can test the coil with a DVOM. Its easy and straight forward but a little tricky to get the probes in the coil harness to check primary. (with the coil on the vehicle... at least on my 97... it faces toward the rear... note - the harness disconnects with a PUSH... don't break it by spreading it upward) Coil specs are in Haynes and Chiltons. Secondaries are tested on top.

Neon spark testers are cheap and good to have around.

Even if it is not the problem - test it anyway! to put you suspicions to rest. I find it sometimes helps to learn and how things all tie together.

note big e's point about cracks

Heh, the plug to my coil is already broken. Thats not my problem though.

Hey Big E my engine shakes like it has a mis. I cleaned the maf sensor, and plugs and wires are only a year old. any clues on what to check or do?

thanks