# Intermittent spark plug fire **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** ignition, trucks, jeep\ **Created:** [September 27, 2009, 4:08pm UTC](https://community.cartalk.com/t/intermittent-spark-plug-fire/37232 "2009-09-27T16:08:28Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![dagriffin](https://avatars.discourse-cdn.com/v4/letter/d/cab0a1/32.png) [@dagriffin](https://community.cartalk.com/u/dagriffin)\ **Post date:** [September 27, 2009, 4:08pm UTC](https://community.cartalk.com/t/intermittent-spark-plug-fire/37232/1 "2009-09-27T16:08:28Z")
I have a 1977 Jeep J10 Pickup. After a while, it quits running - no fire. I can replace the ignition module or wait 20 minutes for it to cool and it will fire back up. I have replaced the ignition module, as well as the pick up and distributor - same things happen. What else could it be? Click and Clack said a few weeks ago that they replace something every time they replace the ignition module. Anyone know what that something is and if my Jeep has one? ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [September 27, 2009, 4:24pm UTC](https://community.cartalk.com/t/intermittent-spark-plug-fire/37232/2 "2009-09-27T16:24:21Z")
The ignition coil might be the problem. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [September 27, 2009, 5:06pm UTC](https://community.cartalk.com/t/intermittent-spark-plug-fire/37232/3 "2009-09-27T17:06:00Z")
How old are the cap, rotor, wires, and plugs? If there’s high resistance in these components, it can overdrive the ignition module causing it to overheat. Tester ---
**Author:** ![Cougar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cougar/32/21348_2.png) [@Cougar](https://community.cartalk.com/u/Cougar)\ **Post date:** [September 27, 2009, 8:44pm UTC](https://community.cartalk.com/t/intermittent-spark-plug-fire/37232/4 "2009-09-27T20:44:59Z")
Have you verified that power is getting to the igntion system when the trouble occurs. If not, you should do that. ---
**Author:** ![dagriffin](https://avatars.discourse-cdn.com/v4/letter/d/cab0a1/32.png) [@dagriffin](https://community.cartalk.com/u/dagriffin)\ **Post date:** [September 28, 2009, 5:49pm UTC](https://community.cartalk.com/t/intermittent-spark-plug-fire/37232/5 "2009-09-28T17:49:10Z")
The cap and rotor are brand new. Wires and plugs, not sure - likely pretty old but there have been very few miles put onto this engine. I bought a re-built engine about 5 years ago - they more than likely used all of the old components (wires, plugs, etc). Not sure about the coil either - likely old as well. There is no fire going to the plugs when this happens. Used a spark plug lite wire to test. What Tester says makes sense - the overheating part. I can replace the ignition module with a “cold” one and fire is restored - until it heats again. So the resistance is what I think I need to get rid of. ---
**Author:** ![tardis](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tardis](https://community.cartalk.com/u/tardis)\ **Post date:** [September 28, 2009, 6:14pm UTC](https://community.cartalk.com/t/intermittent-spark-plug-fire/37232/6 "2009-09-28T18:14:27Z")
I’d bet on the coil. ---
**Author:** ![markmast](https://avatars.discourse-cdn.com/v4/letter/m/4af34b/32.png) [@markmast](https://community.cartalk.com/u/markmast)\ **Post date:** [September 28, 2009, 6:50pm UTC](https://community.cartalk.com/t/intermittent-spark-plug-fire/37232/7 "2009-09-28T18:50:23Z")
I’ll also vote for the coil. If you can check the resistance of the coil, check it cold and after the engine quits. You will probably see a huge difference.