1992 Nissan Pathfinder. Smog test aborted due to "unable to stabilize in the required time".
When the truck reaches normal/warm operating temperature it seems to surge a little mostly in 3 and 4 gear at around 30-40 mph. When the truck is cold it seems to run fine. When we took it to smog they said they aborted the test and the reason stated was "unable to stabilize in required time" The VIR report says "truck surges or lugs down during test."
We have replaced fuel filter, air filter, distributor cap, rotor, and checked all vacuum hoses. We are wondering if you have any ideas to go from here? We did recently have the High Pressure Power Steering hose start leaking and then we replaced it which seems to be about the same time we encountered this engine surging problem. Is there anything that may have cause this from the PS hose, switch etc.? The smog technician said something about the truck having problem like it's under load? Not sure what he meant. Oh and I also took it to a smog shop and they thought they fixed the problem by tighten some bolt and said timing was a little off but they corrected that; Neither of which solved the problem. Answer:
Sounds like your Nissan Pathfinder is suffering from a vacuum leak. You'd
need to get this verified by an expert smog check station, not simply an
auto mechanic. The question which needs to be answered is where is the
vacuum leak? A smog repair station can diagnose this problem using a propane
enrichment tool by presenting propane in and around areas on near your
Pathfinder's engine where a vacuum leak might be present. They can then pin
point the location of the leak and perform the required repairs.
posted by SmogTips Support
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