Joker4096

iTrader: (2)

So I changed all the plugs to new OEM plugs about a month ago. After leaving the battery off for about 4 hours, once everything was buttoned back up, the car would idle very low at about 350 rpm, almost stalling. This went on for a few days until the car relearned itself. I've pulled the battery before and this never happened. Everything went back to normal after driving the car for a few days. Anyone know why this would happen? It was a little scary at first lol.

KraziAzn

Where did you buy your spark plugs at?

Joker4096

iTrader: (2)

From a user here on the classifieds. They are original Denso.

flowrider

iTrader: (9)

I'm not saying this happened to you, but buying new spark plugs from a user here sounds a little suspicious. I encouraged some forum members to buy OEM Denso Spark Plugs from a seller (WellJob) on eBay. The plugs turned out to be counterfeit. I am ashamed of myself for giving this bad advice. The phony plugs were done up very well and fooled the heck out of me. It wasn't until some months later when I checked them against the real thing did I realize what I had done. My knock off plugs are sitting in my tool chest in the garage.

MORAL - DON'T EVER BUY SPARK PLUGS FROM A SELLER IN CHINA OR FROM EBAY - NEVER!!!!!!!!

Lou

joedaddy1

iTrader: (1)

Wow.. would love to see pics of difference!

Joker4096

iTrader: (2)

I've seen those pics in the original thread.

flowrider

iTrader: (9)

^^^^

https://www.clublexus.com/forums/is-...008-isf-5.html

Lou

KraziAzn

There is a good chance the plugs are counterfeit if that is the case. Take into a shop and have them take a look at it.

Joker4096

iTrader: (2)

This is what the spark plug looked like that I put in there. Identical to the ones taken out as far as I could tell.

ultimase

If the plugs were fake then the condition wouldn't have likely resolved by itself. Odd that it resolved itself over time, normally if people have difficulties with idle right after a spark plug change it's putting the wrong lead on the wrong plug, but again that wouldn't have resolved.

Joker4096

iTrader: (2)

Yea the car drives like a dream, idle is much smoother than before. I am going to try to get a virtual dyno to see if there was any power gain vs the old dirty plugs.

UCrazyKid

Could it be a gap issue?

ultimase

gap doesn't close after use, gap typically opens up as they wear.

lobuxracer

iTrader: (2)

It's a lot scary. Something is still wrong even if the ECM adjusted for it. Idle should never be below 600 rpm under any condition with everything working correctly, even if you disconnected the battery for a month.

Find someone with Techstream and do a health check on the computers to see if there are any DTCs pending or present. From your initial comment, it sounded like the fuel lines were hooked up backward (AMHIK), but that situation absolutely does not resolve itself, and the car can't be driven in that state.

Joker4096

iTrader: (2)

I have techstream and will do the health check here soon. I didn't touch the fuel lines at all but it did sound like it wasn't getting enough air or fuel pressure. I do have an afe dry filter installed and aftermarket intake elbow. The only thing that I touched was the fuel resister that I had to unbolt and also the brake booster vac line. I think the check valve is going bad because I have a stiff pedal in the mornings and when trying to start the car after it has been sitting for a while.