Zlut

iTrader: (1)

First off, here is info on my 2003 350z
99,xxx miles
6 speed manual
MODS;
Z1 test pipes
Z1 lightweight flywheel and 6 puck clutch
stock intake
eibach sportline lowering springs
custom blast pipe exhaust from mid-pipe back


As of yesterday, I started my 350z from eating lunch with my fiancé. My gas tank was on E. I pulled out of the parking lot(before this, car has had ZERO ISSUES), I floored it in 1st gear and let out because I came up to a red light. Went to go do it again, and at WOT car started sputtering, losing power. So I let out of the gas, and let it idle. Put my foot into it again, loss of power and sputter at more than 25% throttle. NO SES LIGHT CAME ON. I do work at a dealership, so immediately I pulled the car in and asked my Shop Foreman what could possibly be the issue. I told him my gas tank was empty, he said it maybe picked up some trash from the fuel tank and sent it through the lines and clogged an injector. So I went and put $32.62 worth of gas in my car. Put it a little above half a tank. Drove the car out of the gas station, floored it, WOT, still sputtering and dying out. So after this I assumed maybe my spark plugs needed change, I pulled cylinder #1 spark plug, it had normal wear and build up on it. I did remove the pcv valve hose on the passenger side valve cover so I could access the coil pack. The hose cracked at the end where it goes on into the upper intake manifold. Thought nothing of it, put some electrical tape on it and clamped it back on. It was a slight crack and was past the end on the where the clamp went onto the hose. I rode with a buddy home from work. I also checked my tps sensor, my intake, my intake box, my filter, my maf(even swapped MAF's with my fiancé's G35),and checked for build up on my throttle body. The vacuum hose on the back of the intake is all good also. I checked the oil(changed my oil 900 miles ago) it was good. Checked my coolant( green and good).

New day, Drove my car home from work, whole ride home the car as spitting, sputtering, jerking, and struggling up hills especially when I had to use some throttle. ( I DO HAVE A MATCO SCAN TOOL, IT READS CEL's, ABS, SRS) My car finally flashed the SES light about 15min into my drive home. I already had the scan tool plugged up and the codes it brought up were:

P0301 Cylinder 1 Misfire
P0171 System Too Lean (Bank 1)

I got the car home, and instantly tried to eliminate SPARK. I unplugged Cylinder #1 Coil Pack Connector and the idle got worse. SO its not a spark issue.

I erased the codes.

I reverted to thinking it IS a FUEL ISSUE. I thought maybe one of my injectors did get clogged or there is something in the lines. I bought some STP Fuel Injector Cleaner just to TRY IT. I did not assume that it would fix the problem. Poured it into my half of tank of gas, started my car, let it idle up to operating tempature and went for a drive. Car is STILL SPUTTERING, and losing power. Car loses all power when more than 25% throttle. Got the car home, let it idle, checked for codes, pulled up ONLY

P0174 System Too Lean (Bank 2)

Cleared it, let my car keep running, while I was checking over vacuum hoses and near the upper intake manifold and did hear a hissing. DO NOT KNOW WHERE IT IS COMING FROM. I tried to pull the connector for INJECTOR #1 off but couldn't get my fat fingers in there. So I do not know if INJECTOR #1 is clogged or bad. Finally after idling for about 10min the car finally died out and will not start back up.


I explained everything that has happened since the problem has started. I am asking for HELPFUL, ONLY HELPFUL information please. I am stuck as to what is wrong. I am going to unplug INJECTOR #1 tomorrow at the shop to see if idle doesn't change if I can get my car started in the morning lol. Anyways, if you have any helpful information at all or know someone who had this EXACT problem. Please let me know. Thanks Guys.

engleman

iTrader: (1)

90% of drivability concerns are fuel related. I once had a co-worker, retiring master tech, that told me I could call him anytime I needed guidance. He stated, however, that if I did not have the current fuel pressure reading that he would hang up on me.

I would suggest you start by pulling your fuel pressure at the rail, seems as though that would be ideal since you are lean on both banks. You should also just go ahead and swap injectors and see if that misfire moves.

Come back with those results and I'll be watching for a reply.

koren

iTrader: (23)

Zlut, have you figured out what the problem was?

I have similar situation.
In my case it is P0301 and the other code for the wideband A/F o2 sensor (forgot the bank), says it is running lean also.
Mileage is 13 MPG
thought it was bad coil, replaced it - ran for 2 days and then misfire occured again.
Spark plugs has around 25k miles on them, will try to change Cyl#1 plug but I doubt it will solve the problem.

Ideas?