hi guys, i have a 99 i30 with a sputtering issue.

the sputtering starts between 1500-2000rpm under light pressure on the gas. this happened when i got a phone call that my wife was having contractions while i was at work so i slammed on the gas before i realized my gas light was on. so of course, i thought it had something to do with maybe a dirty fuel filter being as how it's a 99 and i'm sure it was never changed before i got it. when coming to a stop at a trafffic light or a stop sign, the car kind of jerks like it wants to shut off, but never drops more than 100rpm.. it's constant between 750 if i have the a/c off and 900 if i have the a/c on. never drops low enough to shut the car off *KNOCK ON WOOD*. i do have the SES light on but that's an O2 sensor on the rear manifold that i have to replace.

so yesterday i bought the fuel filter and replaced it, car still sputters. then i was told to try spraying brake cleaner on my vacuum lines and if it sputters, that would be my problem. so i did that and it turns out there was a little crack on the rubber hose from the hardline to the pcv valve on the intake manifold by the TB. changed it and still sputtering.

now, i did notice that right by the rear part of the UIM there is a hissing noise like if there was a vacuum leak, but i can't pinpoint it. i've changed my rear exhaust manifold gasket a while back and UIM gasket while i was at it. i'm convinced this is a vacuum leak issue, although a minor one since the car has yet to shut off on me. EDIT: forgot to add that i also bought a can of seafoam and used half through the intake manifold, a friend of mine swears by it and i could've sworn i read somewhere on here that it helped them with there sputtering issues. as you can tell, still sputters

any and all help is appreciated because this is my daily, i just had a baby girl and definitely can't afford costly repairs. i'm definitely good with tools and don't plan on giving a shop my money if i can help it. thank you for taking the time to read this.

 

congrats on the little one!

when you said you floored it and it sputtered, did it rev up all the way? if yes, was acceleration sluggish?

i'm thinking maf sensor. these are expensive from the dealer so don't hurry out and get one...and non oem ones off ebay suck dirty *** hole hairs! if it turns out to be the maf (and a lot of the time your ecu won't show a code, me included) then go to the junkyard and yank one off, 2 mins and it they will charge around $50.

more details would be helpful

 

Well, under heavy acceleration the car doesn't exactly sputter, but u can feel where the car catches the acceleration. I don't think I can explain it right through text. Its like I can feel the car pick up, and then throughout most of the mid range I can feel where its holding back and then picks up again. Dunno if that helps.

I also checked all my coils, but not the way described in other threads I've read since becoming a member. I pulled them out and checked with a screwdriver and all 6 packs were showing blue spark.

Could be MAF sensor now that I've been reading around more, I had to replace it about 2 yrs ago with an autozone one when I was installing my intake when I first bought the car. I ended up breaking it by leaving it on the floor in the driveway and my friend running it over lol.

I'm really leaning towards a vacuum leak because of that hissing right by the rear of the UIM.

Thanks on the congrats BTW lol

 

So today I get to the parking lot at my job and notice that my radio was shutting off and turning back on and my lights started to dim. Got safely into a parking space turned her off and she won't turn back on. So I have a shop next door check it out, alternators shot.