Northstar Misfire... no error codes

[akimball442]

1998 Seville SLS

I was on the NYS thruway today, and as I began climbing a hill, I noticed the engine beginning to miss like crazy. I've never had a 96 or newer vehicle that didnt start flashing the check engine light during this condition. So once I got done with the hills, I punched it a few times, and sure enough, under load it misses like crazy... for the most part. Sometimes it's ok. What would suddenly cause this? Cruising and normal driving are fine. Gas mileage is fine, car is otherwise in good condition.

64000 miles

Any ideas?

Aaron K

[Ranger]

Plug wires. Stick with A/C Delco.

[akimball442]

Wow, the AC ones are sure expensive... oh well, guess that's the price you pay for driving a cadillac. I just wish this car wasnt constantly nickel and diming me to death.

[dkozloski]

Originally Posted by akimball442

Wow, the AC ones are sure expensive... oh well, guess that's the price you pay for driving a cadillac. I just wish this car wasnt constantly nickel and diming me to death.

What do you mean by nickel and diming? It's dollaring isn't it?

[thu]

Are you sure it's missing? Perhaps the engine is starving for fuel? From your symptoms, it happens only when you want more power but is fine otherwise. This is typical of a plugged filter or malfunctioning fuel pump.

[dkozloski]

Opening the throttle increases cylinder pressures which increases the voltage required to jump the gap of the sparkplugs. The same increase causes the spark to jump to ground through flaws in the plug wire insulation or some place in the ignition. I'd look under the hood with the car in as dark a place as I could find and the engine running. Spray water on the plug wires with a spray bottle. If the wires are bad you'll know right away.

[Ranger]

[joe_padavano]

I had exactly the same problem on my 93, and it got steadily worse. Since the car had 80K+ miles, I replaced plugs and wires first, but that did not fix the problem. I replaced the ignition module and coils next, and the car has never run better. Be sure to get an AC Delco ignition module (though be prepared for a $350+ price tag). I used MSD coils instead of Delco because they were both less expensive and higher voltage (though they are bright red).