- This topic has 8 replies, 2 voices, and was last updated 8 years ago by
.
- Topic
2005 T and C. 3.8 L 80K
Codes P0304 and P0300. Did not look at live PID yet. Freeze frame showed normal fuel trims. Only did quick check with Bluetooth scan tool and told him we could diagnose this Saturday. I am familiar with why misfires happen and what to check. My questions is: Is anyone familiar with common failures in this vehicle that would speed up diag with problem listed above. His plugs are probably original with everything else so I did tell him new plugs were in order but don’t want to put in $ in vehicle until we know his problem. Thanks in advance.
- Replies
Try a power balance test. you could also check for spark at each plug.
https://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Thank you for getting back with me. I may have asked my question wrong. I understand how to diagnose misfire. I was asking if anyone new of a common failure on these vehicles such as bad injector or coil just to start with just to save time etc. Thanks anyways though.
[quote=”jjohnson1″ post=182798]Thank you for getting back with me. I may have asked my question wrong. I understand how to diagnose misfire. I was asking if anyone new of a common failure on these vehicles such as bad injector or coil just to start with just to save time etc. Thanks anyways though.[/quote]
😉
Ever here of O2 reading high, obvious misfire but fuel trims not compensating. Only spent about 10 mins looking at PIDs in brief run by to pick up kids. I understand O2 readings and Fuel trim data but why would O2s read high and not have a reaction out of fuel trim. The only thing that comes to minds is bad data from scan tool or cpu.
also did not have dark smoke or rotten egg smell. just missing out exhaust with light shake of engine almost more of a fish bite. I am thinking a good set of plugs are order but will check injector and so forth. My question specifically is to o2 reading and expected fuel trim adjustment not aligning.
[quote=”jjohnson1″ post=183063]Ever here of O2 reading high, obvious misfire but fuel trims not compensating. Only spent about 10 mins looking at PIDs in brief run by to pick up kids. I understand O2 readings and Fuel trim data but why would O2s read high and not have a reaction out of fuel trim. The only thing that comes to minds is bad data from scan tool or cpu.[/quote]
If the o2 is stuck rich the fuel trims won’t want to move.
The above misfire turned out to be just spark plug as expected. As far as o2 data, when I rechecked it was fine.
- You must be logged in to reply to this topic.