Well a little background on the car... 95' ESI, headers, 2.5" catback, aem v2 intake, and modified jeep tb (I believe 57mm). Also has cruise control that when I had the oem steering wheel use to work and then randomly cut off like it lost vacuum for a second which may be irrelevant. And it has over 210,000 miles.

The car has always had really low vacuum from the time I bought it stock (idles around 8-10inhtz) that has remained consistant with all of the mods and replacement parts I've done. Recently it started a random hesitation/stutter that has gotten worse with time. I've searched for a really (REALLY) long time and haven't found anything like what I am working with here.

Basically at idle, sounds like it has a set of stage 2/3 cams. Lopes real good for no reason. I also notice that it seems to run very rich at idle. You can smell raw fuel coming from the exhaust with black soot inside and around the silencer. When I'm driving it, feels like it's a bit sluggish at low rpm, under around 3500, then between there and about 5500 it pulls hard, and falls flat on it's face around 6k. It's almost like it's got a constant fuel pressure that stays the same through out the power band.

Now the misfiring deal. It has a funky little hesitation that sometimes gets worse and worse the more I drive it. It seems to happen more when the load changes, ie- up or downhill. Sometimes it seems like the primary or secondary coil just stops firing for a little while, and then it picks back up like normal. It has also been hitting fuel cut from time to time, and the only way to get it to stop is to shut it off and fire it up again. I know, wtf. It's throwing a p0351 code- primary, secondary ignition coil malfunction.

Here's what I've replaced so far...

Plugs twice, wires twice, new ignition coil twice, reman ecu, fuel filter, oil sender unit, vacuum guage, all new vacuum lines except for the vacuum box (if it has one, I know 97's with cruise control have them). I also did a compression test on it, 160/145/160/160. I don't know if that's too good of numbers but it seemed to do fine before.

I don't think it has a vacuum leak since it doesn't idle higher than normal like it does if I disconnect a line. A buddy of mine checked it out and said could be a crank, cam, or knock sensor throwing off the ignition timing which makes sense to me. I was also thinking maybe the iacv since sometimes it will just die during warm up but start right back up.

But I'm tired of just replacing parts and I need some opinions or knowledge on how to test some or all of these pieces.

I CONTRIBUTED TO THE WIKI!
ah... turbo. I love the turbo, the boost, the speed, the sound.
and its all better when you do it yourself. cheaper too.

Anyone? I'm on vacation until friday so if there's time to fix this issue(s) it'd be now.

I CONTRIBUTED TO THE WIKI!
ah... turbo. I love the turbo, the boost, the speed, the sound.
and its all better when you do it yourself. cheaper too.

Update: Replaced the coil pack with a msd unit and electrical taped the connections for the connector. Seemed to smooth out the idle a bit, and hesitation was gone on test ride.

Usually it seems to start out good and sort of slowly get worse and worse until I change out the coil with a new one and then it rides like normal for a day and starts the whole process over again.

I'm guessing as far as the hesitation goes, there must be a short somewhere from the ecu to the coil pack. I have swapped the plug twice (from a 95 to a 97+ and back to a 95), but this has just started happening. The last time it was running this bad was when my MSD box fried, which is no longer hooked up. Runs off of what seems like two cylinders.

I get very little acceleration if any, and when I pull the wires off of the plugs with it running, idle drops for each cylinder and you can hear it sparking out of each wire. It just doesn't seem to be firing every time. It's almost as if the primary coil fires and skips and fires and skips, while the secondary is doing the same but on a different beat. She actually sounds like a lawnmower when this happens.

I CONTRIBUTED TO THE WIKI!
ah... turbo. I love the turbo, the boost, the speed, the sound.
and its all better when you do it yourself. cheaper too.