My 99 Z has been misfiring at wide open throttle. This problem came on very sudden a couple days ago after I mashed down on the pedal to merge intyo traffic.
It originally threw a P0300 (random misfire) but after the plug change it isn't showing any codes. While normal driving it isn't noticable or at least I don't feel it hesitating.
I also can hear it sometimes when the hood is open . I hear it arching and it sounds like a tight snap sound coming from by the IDI cover. I'm also pretty sure it only
happens when the car is warmed up. I switched out the coils, ignition module and plugs all separately to see if was one of the more simple fixes. Before I changed
the plugs when the hood was open it was happening almost 1 to 2 times a second. The snapping only happens randomly now, more like 1 to 2 times every 15 seconds.
The white platic housing under the IDI cover is in perfect condition so I know it isn't that. I checked older posts and they don't quit sound like what's happening here.
Any suggestions would be greatly appreciated.
Edit: It is only happening when the car is warmed up to operating temp and I give it full throttle.
It sort of hesitates when I press down and then frees itself. I don't hear the snapping any more
though when the hood isopen.
Edt again: I changed the Throttle position sensor, MAP sensor and idle air control sensor and nothing. Is there any thing left?
The coil housing or white plastic part may look ok but it is not.That will be my first suspect.
i agree with Luis. the snapping is the sound of the power arcing between a crack in the plastic and the block. with the high voltages that run beween the coils and the plugs it doesn't take much of a crack for the power to arc out from the conductors molded into the plastic to the block.
Thanks for the responses. So its possible for it to be bad but not visibly cracked? I just changed it not more than 7 months ago(approx 3000 miles.)
They go bad that quick? I called the local parts store and they have it in stock so I'll switch that tonight and see what happens. Thanks again fellas.
if you recently changed the cover it could be the boots. (the grey rubber peices that attach to the plugs) might want to look into that
PROBLEM FIXED......
Amazing! I tried the housing and guess what. I still looked it over and over afterwards and it looks brand new??
There was no black marks from the misfire like my old one had done before. Maybe it was in between the palastic.
where the wires run. The new one is a black plastic. Hopefully it isn't just a color change and maybe a change in the
plastic they make it out of. I hope this helps somebody with the same problem as this one really had me stumped.
Thanks to you guys for the little push to try that as I never would think that it was the coil housing again.
sweet good luck with that cover. hope it lasts longer than a few months
