If he/she has the right scanner, he can drive it and watch and see what is going on when it actually happens.
P0300 error after new plugs and wires
- Thread starter jonp365
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Well, I got to pay the "stupid tax", but it was only $105 for diagnostics, so it could be worse. Misfire was coming from #8 cylinder. When I was double checking the 2, 4, 6, and 8 wires, I didn't remove the wheel and liner to get good access, I simply reached in. Apparently I did not fully seat the wire and my double check was not good enough to notice it. I should have taken the time to do the check properly. It explains why driving around the neighborhood and anything lower than 50mph/4k rpms didn't reproduce the issue. It only happened when I really got on the accelerator...when #8 would have been required. So they fixed my poor seating job and its all good. First time I've done spark plugs on a Tahoe, so learning experience. Mental note for next time...in another 100k miles. Maybe this will help someone. Thanks to all who helped and gave me advice!
Just today I replaced the valve cover gasket on a 1986 Nissan pickup 2.4. Has 2 plugs per cylinder. I checked the plug wires that he paid someone, about a year ago, to replace with the 8 plugs. The back d/s wire was not seated on the plug tip. I could wiggle the plug boot like the plug tip was broke. I drove it before working on it, I always do. Had a slight ruff idle and misfire and he said it was driving fine. I pulled the plug wire boot and all looked good. I plugged back on and felt the click. Smoothed out the idle and now no misfire. Alaways double and triple check your recent work.
