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Newbie here with a question already!! I have a 97 Expedition. It sounds & feels like it is skipping but the check engine light is not on & there are no codes in the cpu. It does it worst when it is under a load like going up hill or pulling something. Sounds like a plug wire but no code or light?! Any help would be appreciated.
You've either got to drive it hard until it pops a code, which BTW takes 2 consecutive trips to set, or you use an OBD-II scanner that reads live data so that you can watch the misfires in real-time.
Thanks for the info. I'll drive it around for a while this afternoon. I'll have to find someone who has a scanner that reads live data. Could a vacuum leak give it the same feel as skipping? As long as the PCV valve rattles when you shake it, it should be ok, right?
Could a vacuum leak give it the same feel as skipping? As long as the PCV valve rattles when you shake it, it should be ok, right?
A vacuum leak tends to give reduced power and/or pinging noises from the engine because of the leaner mixture. The PCV valve is good 9 out of 10 times if it rattles freely. The plunger has to be able to move, but it also has to be able to seal. So just because it rattles doesn't mean it will seal when needed. Making sure it is clean inside helps it to seal.
Do you have the 5.4? It's been a couple years since I had my 5.4 Expy. My new one (which is older) has a 4.6. I had that problem and it was a 90 degree vacuum hose at the back of the engine on the pass side i think on the plentum(excuse my spelling). Just a possibility, worth a check.
You were right alloro!!! Took her out for a couple hour road trip yesterday and she finally popped a code! Misfire on cylinder #3. What's a good OBD II scanner that reads live data? Thanks again.
Yes, it is a 5.4.
William
Last edited by 85redevil; Jan 22, 2014 at 06:43 PM.
Reason: added info.
Glad to hear you popped a code....I was in a similar boat and wound up replacing 3 COPs and 3 plugs. Expy runs super nice too.
I have a ScanGauge II that reads signals from PCM so I can see "live gauges", but it doesn't do too much more than that..well it reads codes if you get them to trigger and reset. I got mine from Advance Auto Parts for 116 out the door (with on-line coupon). However I will be looking for something a bit more in-depth in the future.
Good luck with repair!
Last edited by DEMIGOD; Jan 22, 2014 at 08:06 PM.
Reason: Too many spelling errors...