Help diagnosing a misfire
Thread Starter
|
3rd Gear
Joined: Sep 2023
Posts: 3
Likes: 0
Help diagnosing a misfire
Hi everyone, just bought a 1990 f250 with a 5.8. Ive had an issue with the battery draining over night. Ive been just disconnecting the negative bat cable for the past week. Previously I would hear a clicking coming from the pcm relay everytime i would touch the cable to the battery even with key off. I did something and now it doesnt click and now it doesnt drain. However recently Ive noticed something that sounds like a misfire. I can hear it a lot on the passenger side due to an exhaust leak there. I went to the tailpipe and it def sounded like one as well. I pulled two plugs on teh passenger side and i was told that im running lean right now. Does anyone think theres a correlation between the battery drain and the misfire? Also i dont hear it when i rev it in idle, its only under load where i really notice the loss and power and sound of the misfire. Also whenever I press the brake pedal down it sounds like air is being released somewhere, maybe a possible vac leak. Would this contribute to the misfire if i did have a vac leak? Anything would be appreciated, thanks.
Laughing Gas
Joined: Jan 2023
Posts: 1,172
Likes: 114
Vacuum leaks will cause a misfire, probably why your lean to. I had a connector break on the vacuum line and it had a bad misfire at idle, and especially accelerating. So I would look for that vacuum leak.
I would check the plastic vacuum lines on the passenger side, those are very very brittle if they never have been changed.
I would check the plastic vacuum lines on the passenger side, those are very very brittle if they never have been changed.
Thread
Thread Starter
Forum
Replies
Last Post
Oversized Chuck
1997 - 2003 F150
0
May 7, 2017 09:17 PM
