The Nissan Path

Hi Guys,

Anyone know why my engine is surging? It happens when I accelerate for a bit then if I let go of the gas the car surges forward. Also on the freeway the car seems to lose power and "dies" for a second then goes back to normal (scary moment). Are this both related? And can this problem also explain my car randomly shuts off like on a stop sign? I already replaced the IPMI fuse and based on the carfax report, it the ECM has been replaced.

I just want to ask you guys first before going to the auto shop since I want to make sure I'm not being overcharged.

Thanks!

Lean conditions often cause surging. You might what to make sure your MAS hotwire is clean and if there's a screen in front of it, make sure there's no debris stuck on it. Then I would check the fuel pressure. If you don't have a scan tool to view datastream info, it might be tough to go much farther with the diagnostics. If you have over 100,000 miles on the spark plugs, that would be another thing to check, as well as your vacuum lines and rubber intake duct connectors for splits.

Thanks for your reply smj! One more thing, is this also related to the Engine dying randomly? Thanks!

It could be.

Hi again, just to give you an update, the "experienced and highly yelp rated" shop that I brought my car into can't duplicate or find the problem. I don't blame them coz as I've said, this all happens randomly. Their conclusion was either a crankcase (or crankshaft, I forgot which exaclty) position sensor malfunction, or ignition coil problem. Do you think what they said would be plausible?

Thanks so much!

I'd bet it is electrical problem, not mechanical. So I'd forget about crankshafts and crankcases.
What I'd do first would pull out diagnostic codes. You can do it yourself with cheap ELM327 OBD2 bluetooth reader from eBay (10 US$), get an app to your smartphone (like Torque or something else) and off you go with DTC codes. I bet there's some DTC code in there.

We've had more problems with cam position sensors than crank position sensors, but they are possibilities and sometimes will not trigger codes. Coil packs will usually trigger a code, specifically a P1320 and/or a cylinder misfire code (P0301, P0302, etc.). It's difficult to diagnose something if one can't duplicate it on a consistent basis.

Hi everyone, just a quick update. We found the problem already, and it turns out to be a very bad valve gasket cover and really worn spark plugs. All the plugs are almost covered in oil, causing the misfire, the surging and the random dying. The guy who I bought the car lied to me about replacing the spark plugs at 100k service coz cleary they're still the original spark plugs. I also checked the carfax records and those were never replaced.

Lesson learned: when buying second hand, always ALWAYS ask for service records/carfax.

Thanks guys!

If oil is sitting on top of the spark plugs, then it's the spark plug tube seals that are leaking, not the valve cover gaskets. To replace the spark plug tube seals on the VQ40DE, you have to replace the entire valve cover; you'll still need the valve cover gaskets as they don't come with the new valve cover.

Thank you so much SMJ! Already told my mechanic about that, and they're now replacing that too.






I can see my $$$ flying.

I have the same problem. Replaced plugs and the #2 cam position sensor plus a clean of the intake system and still have the same problem. Just finished a transmission replacement which I was hoping would fix the idle problem. Mechanic reset the idle so I'm wondering if it's a crank position sensor...there's no consistent pattern in when it happens and it just started about 6 weeks ago, 140K miles.