I’ve been dealing with family and health issues and not driving my 2005 GT a lot.
I took it out for a run and it stumbled at about 100mph under WOT. No active codes but I checked stored codes and it had P0340. PA alternator is working fine.
Before this happened, I noticed the a/f was running lean. At one point, the Interceptor gauge was stuck at 19.9. They are not the most reliable. Recalibrated, at it was at high 14’s.
Last week I changed plugs. It’s been over two years and with the SC it was due. Plugs looked normal. Took the car out to dinner and on way home when I went 50% throttle, it started to shudder.
I double checked all wires and air filter since I cleaned that also. It’s a dry Amsoil filter. Cleaned MAF, and looked up how to test with multi-meter. It is getting 12V constant power with KOEO, but when I checked for continuity for ground, I couldn’t find any. I peeled back tape to get to main wire harness, cut insulation as shown in photo, and with KOEO, neg lead hooked to neg terminal, the positive probe does not beep when I touch the black wire with white stripe. It will beep if I touch good ground source. Does anyone know where that wire goes, and what to test next?
Car will start and run great if driven easy.![IMG_0684.jpeg IMG_0684.jpeg](https://www.s197forum.com/data/attachments/74/74659-e5479cb85c77bade9c925b667642f308.jpg)
I took it out for a run and it stumbled at about 100mph under WOT. No active codes but I checked stored codes and it had P0340. PA alternator is working fine.
Before this happened, I noticed the a/f was running lean. At one point, the Interceptor gauge was stuck at 19.9. They are not the most reliable. Recalibrated, at it was at high 14’s.
Last week I changed plugs. It’s been over two years and with the SC it was due. Plugs looked normal. Took the car out to dinner and on way home when I went 50% throttle, it started to shudder.
I double checked all wires and air filter since I cleaned that also. It’s a dry Amsoil filter. Cleaned MAF, and looked up how to test with multi-meter. It is getting 12V constant power with KOEO, but when I checked for continuity for ground, I couldn’t find any. I peeled back tape to get to main wire harness, cut insulation as shown in photo, and with KOEO, neg lead hooked to neg terminal, the positive probe does not beep when I touch the black wire with white stripe. It will beep if I touch good ground source. Does anyone know where that wire goes, and what to test next?
Car will start and run great if driven easy.
![IMG_0684.jpeg IMG_0684.jpeg](https://www.s197forum.com/data/attachments/74/74659-e5479cb85c77bade9c925b667642f308.jpg)