Lariat Posted November 15, 2022 Share Posted November 15, 2022 My 1994 Pathfinder has the check engine light come on at full stop. Then goes out after getting up to speed. Light otherwise does not come on. The ECU always reads 55(no malfunction). Truck runs and idles smoothly, no hiccups on acceleration. Anybody have similar issue? Any ideas? Comments? Thank you in advance. Link to comment Share on other sites More sharing options...
SkiBumBrian Posted November 15, 2022 Share Posted November 15, 2022 Although mine is '91 I had the exact same symptoms. I found it to be a small vacuum hose on the back of the engine, center top. It had cracked at the end and fallen off. Trimmed it, plugged it back on the nipple, problem solved! Does sound like a vacuum leak somewhere.... Link to comment Share on other sites More sharing options...
Lariat Posted November 15, 2022 Author Share Posted November 15, 2022 Thanks SkiBum. I have a feeling you are right. Some vacuum hoses are pretty brittle and old. I’ll check now and reply! Link to comment Share on other sites More sharing options...
Lariat Posted November 15, 2022 Author Share Posted November 15, 2022 47 minutes ago, Lariat said: Thanks SkiBum. I have a feeling you are right. Some vacuum hoses are pretty brittle and old. I’ll check now and reply! Well, well SkiBumBrian! I checked as you suggested. From the back of intake manifold, center engine, close to firewall, wouldn’t you know! A small vacuum line, and when I touched it, it disconnected from manifold nipple. A half inch split on the end, so of course no seal. Snipped off the end and stuck it back on. Haven’t driven yet, but have high hopes!! My further question; how in the world did you find this line other than just pulling on lines?! Anyway, thanks so much for feedback. Hope this an irritating issue! Link to comment Share on other sites More sharing options...
gamellott Posted November 16, 2022 Share Posted November 16, 2022 As far as finding the hose, I discovered it when I was changing the spark plugs and it ran like crap after the job. Same thing, found the hose cracked and I have since replaced it. Truly an obscure little hose.... But now that you know about it, you'll know where to look Link to comment Share on other sites More sharing options...
Lariat Posted November 16, 2022 Author Share Posted November 16, 2022 Thanks gamellot. I’ll be getting some vacuum hose to put in my kit. My rig ran fine, but just the issue with the CEL when stopped. These issues that pop up now and then just give our rigs more character! 1 Link to comment Share on other sites More sharing options...
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