Coil Packs and RPMs

[bowtieguy]

my mechanic seems to have a theory on my intermitant acceleration issue(hesitation) on my 2000 chevy prizm. he believes it's a coil pack starting to go bad, but could not replicate the issue. since it cannot be isolated, he said we should wait for it to get worse.

2 questions...

he rode w/ me to see if we could replicate the problem. he then accused me of causing the issue because i shift ~2k rpms. he said this could cause coil pack issues among other things, and suggested 2500 as a shift point. i say that's garbage. your thoughts?

next. i think outside the box, so...what if i bought 1 coil pack, installed it, then drove to see what happens. if it continues, i'd pull it, move to the next one, and repeat until the bad one is found.

to me this is a better option than trying to drive home on 3cyl at some point when it finally fails. again, your thoughts?

[Ford Man]

I think your mechanic is crazy. What is RPM going to have to do with the life of a coil pack? My '88 Escort Pony has 496K miles and still has the orignal coil on it and I shift at low RPM's and have ever since I've owned it. If you have service/repair manual there's probably a proceedure to test your coil pack. I know they can be tested on my Escorts. You should be able to pick up a repair manual at Advance or Auto Zone for about $20. and is money well spent.

[GasSavers_RoadWarrior]

I've got a similar issue on Wile-E don't know whether to finger the coil pack yet or not, it's driving me nuts.

[GasSavers_Pete]

Your mechanic is not totally wrong.
The load on the engine will show any faults in the coil pack when the load is higher than normal and low RPM shifting will make this more obvious.

Try getting the car moving and when in second , let the engine speed drop to about 1500 then try a rapid acelleration. This will load the engine and if there is any problem with the coil pack it should show up then.

It may also be needing new plugs , leads or whatever so this is a guide only.

Cheers , Pete.

[theholycow]

When diagnosing someone's equipment, it's hard to avoid blaming the weird thing that they do that seems like it should break stuff.

Your mechanic may be right or wrong, and your idea for testing sounds like a good idea to me.

[bowtieguy]

still working on it...

replaced 1 coil pack--no change. going to the next one. if they weren't so expensive, i'd just replace them all.

it's so intermitant, it takes a while to get it to act up. so, this may take some time. the ethanol free gas test is on hold!

[kamesama980]

lol then my trucks doomed... I go driving around in 4th (highest gear) at 1000-1500 all the time.

your mechanic is 1/2 nuts. You can't hurt your car shifting at 2k. a corolla/prizm should have no trouble whatsoever shifting there. BUT as mentioned, it may be revealing the problem.

[theholycow]

Originally Posted by kamesama980

lol then my trucks doomed... I go driving around in 4th (highest gear) at 1000-1500 all the time.

Heh...me too, I rarely exceed 1500, and I use WOT most of the time. It's survived 25,000 miles so far.

[bowtieguy]

just an FYI for you all...

i went to purchase a 2nd coil pack from the same part store, different town, to find out it was $10 more.

apparently the price varies even just a few miles away. anyway, i brought this to the attention of the guy at the parts counter, and he said he would match the price.

being frugal, many of us no doubt ask for competitor price matching. i had no idea it would even be needed w/in the same corp.

[kamesama980]

What parts store is it? places like NAPA are all privately owned/operated. the corperate franchise sets their costs and some general rules of operation but actual markup and store operations are up to the individual owners discretion. places like Autozone, which are entirely corperate, will only vary by the local tax (and maybe shipping rates on special ordered parts)