I have a 97 I30 and gosh today was not its day. I have done nothing to cause it to stall or stumble. It has OEM coil packs and NGK plugs with about 10k on the plugs and 192k on the coil packs (I never touched them but if a previous owner did idk).
It is a recent issue, it stalls going up hills and when taking turns sometimes. Feels like its not getting fuel pressure. I have done no troubleshooting yet because it is a brand new issue. I do have CEL's for EVAP like P0440 and P0441. they keep coming back even though i have replaced almost every part pertaining to the EVAP system.
I am currently running 92 gasoline, in an effort to troubleshoot. Where should I look. While searching the forums this issue seems to have a load of causes. It was at operating temp when this happens no issues present there

 

Seems like a fuel starvation issue.

sounds like this happened suddenly rather than gradually?

my guesses.

1. Fuel pump.
Look up how much fuel it's supposed to deliver vs actually does. I would install a hose at the output side of the fuel filter. Put the hose end into a container. The measure after exactly one minute. Compare that to the official fuel delivery rate.

2. Fuel pressure regulator. Remove vacuum hose. Do you smell gas?

 

Thanks I will check that. It was sudden as of Monday 9/13/21

 

Use what ever Scan tool You Got the Codes From, and use its live date Function, Check The Maf's grams per sec rate. Under load. Start the car and do a Simple Wiggle Test. Start at the basics.

 

forgot about the MAF thanks

 

Definitely probably the MAF, mine was doing that for a couple or few months this year. Even multiple shop shop diagnostics didn’t figure out the issue because it would usually “behave” once the engine had been running for awhile. $50 eBay part solved it, though I’d of had a hunch sooner I’d of went with autozone or Napa.

However my 98 Q45 has been exhibiting similar issues, except it’s not stalling and I’ve changed the MAF. I took in for a diagnostic, but other than a dead oxygen sensor, my mechanic suggested it could be water in the tank being it does it moreso when low on fuel…which isn’t surprising considering after a heavy rain or 2, there’s water often sitting under the fill insert.

 

Took the IACV out. Man it was black and very dirty. took it apart and spayed it out. Going to throw it back on the car tomorrow and see if the situation goes away

 

Didn't do a thing... Time to look elsewhere

 

Thinking It might be the MAF. Have not cleaned it or anything. Any brands I should look for?

 

Lol, it was this... threw the one from my 98 Maxima and it didnt die at all today, no engine struggling either.