# Random miss, no codes in computer **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** jaguar, x-type\ **Created:** [November 16, 2009, 7:09pm UTC](https://community.cartalk.com/t/random-miss-no-codes-in-computer/39591 "2009-11-16T19:09:24Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![MikeMo](https://avatars.discourse-cdn.com/v4/letter/m/41988e/32.png) [@MikeMo](https://community.cartalk.com/u/MikeMo)\ **Post date:** [November 16, 2009, 7:09pm UTC](https://community.cartalk.com/t/random-miss-no-codes-in-computer/39591/1 "2009-11-16T19:09:24Z")
I have a 2002 3.0 Jaguar X-Type, 123K miles. Changed the plugs and all of the recommended gaskets using all Jag parts. Immediately after the change, I suddenly have a random miss that only occurs when accelerating strongly at low RPM - like at 45MPH in 5th. It does not seem to miss at higher revs, or when giving it a lot of gas. A little less or more throttle and the miss goes away. Sounds like it’s lean, but everything is torqued and tight. There are no codes coming up according to the nice folks at Autozone. Any ideas about what I should be looking for? ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [November 16, 2009, 9:19pm UTC](https://community.cartalk.com/t/random-miss-no-codes-in-computer/39591/2 "2009-11-16T21:19:55Z")
I once had a similar situation and it turned out one of those new plugs had a cracked insulator on the wire connector end of the plug. ---
**Author:** ![MikeMo](https://avatars.discourse-cdn.com/v4/letter/m/41988e/32.png) [@MikeMo](https://community.cartalk.com/u/MikeMo)\ **Post date:** [November 16, 2009, 10:27pm UTC](https://community.cartalk.com/t/random-miss-no-codes-in-computer/39591/3 "2009-11-16T22:27:29Z")
Was this crack obvious? How could you tell it was cracked? ---
**Author:** ![tardis](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tardis](https://community.cartalk.com/u/tardis)\ **Post date:** [November 16, 2009, 10:46pm UTC](https://community.cartalk.com/t/random-miss-no-codes-in-computer/39591/4 "2009-11-16T22:46:52Z")
Agree. I’d try another set of plugs first. Also, did the OP check the plug gaps and adjust as needed? ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [November 17, 2009, 3:34pm UTC](https://community.cartalk.com/t/random-miss-no-codes-in-computer/39591/5 "2009-11-17T15:34:43Z")
Yeah, it was obvious. It was my first car ('76 l6 Nova) and maybe my second time changing plugs on a car. It didn’t act up right away, so it probably started as a hairline crack. When I pulled the wire boot off the ceramic was in two pieces, held together by the center conductor. ---
**Author:** ![MikeMo](https://avatars.discourse-cdn.com/v4/letter/m/41988e/32.png) [@MikeMo](https://community.cartalk.com/u/MikeMo)\ **Post date:** [November 17, 2009, 10:11pm UTC](https://community.cartalk.com/t/random-miss-no-codes-in-computer/39591/6 "2009-11-17T22:11:16Z")
Yeah, I gapped them all, at the narrow end of the spec. Exactly how does a crack like this lead to the observed behavior, with a miss occurring only within a very narrow band? I’m dying to know! ---
**Author:** ![tardis](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tardis](https://community.cartalk.com/u/tardis)\ **Post date:** [November 17, 2009, 10:34pm UTC](https://community.cartalk.com/t/random-miss-no-codes-in-computer/39591/7 "2009-11-17T22:34:48Z")
High frequency electrical discharge is a very funny thing. It does not always behave the way you might expect it to. You describe the miss as happening when the engine is under the most strain. Maybe it is happening all of the time, but you can only feel it when the engine is pushed the most?