DTN

My engine is stuttering when i give it gas between 0-2,000RPM above 1/4 throttle. It should just be a deep low sound. It is feeling like it wants to stall out or something. I can't figure it out. It has more power when i give it 1/4 throttle then when I give it full throttle. Anything above 1/4 is very jerky. Above 3,000 RPM, nothing is noticably wrong. Idle is somewhat rougher then it should be too. I also have excessive oil comming from my breather.

mods: I run CAI w/ chrome elbow, Headers, and I have run nitrous, but the problem is occuring when i've had no nitrous for about a month.

data: I have no codes. My o2 sensors are relocated one in front and one in rear of the catalytic converter. both are reading normal wave forms, are horizontal with the driving surface, and fully in the path of the exhaust. One wierd thing is when the o2 sensor value rises to rich, it seems that the idle gets slightly rougher. MAF is reading normal, IAT is reading normal, no OBD-II values seem wrong.

Troubleshooting:
verified compression tonight (pulled all spark plugs, let engine cycle 5 times, cyl1- 210psi cyl2-209psi cyl3-205psi cyl4 208psi)
Changed spark plugs, checked gap tonight
ran 2 cans of sea-foam tonight, 1 in gas and 1 in oil (for possible sludge buildup)
verified fuel pressure 38PSI after filter
10,000 miles on wires, spark tester looked fine.
no vacuum leaks audible from top of engine in engine bay

oil change has 1,000 miles on it, 1/2 qt low
fuel filter still has 5,000 miles before change is due

WTF? Give me some ideas here.

Ericy321

Sounds like you have a dead spot on your tps man.

REDZMAN

2 cans of Seafoam?

Tonight?

Uhm...

Ericy321

Ya, definately shouldnt live by seafoam. It isnt recomended to be used that much

CompactDivisions

Three things to check, going on what your describing

Fuel - Filter - check to see that the filter isn't cloged and the proper pressure is getting to the rail.

Spark - Wires - you might have a dead wire, at higher RPMs you might not notice the stutter.

Exhaust - Cats - fouled cat, might be the cat but I doubt it cuase you have power above 3000. If you can drop a pipe before the cat and give it some revs.
I know that this seems odd, but I just had to punch my cat on my other car (civic) lol. Because it was completely plugged, the car started and had sputtering issues and

Some options to check anyway. Hope it helps

DTN

^^ It's only when the engine is under load that it is noticable.

Spark tester definatly showed good spark each and every revoloution.

I will try the fuel filter within a few days. Cat would be a good thing to check as I was running pretty rich for a while.

Is there a way to clean a cat? Can you take a blowtorch and burn deposits, or use an air hose?


TPS seems to be fine. It registers in about 1%-4% increments on OBD.


Yeah, 1 can as a high potency fuel system cleaner, the other to remove any sludge buildup in the engine. I plan to run for a few days and then get an oil change. Basically, I'm trying to either clean out the fuel system or reveal the weak component.

I've had a couple of nitrous backfires in the past. I've run seafoam in my engine before, and it did not clear up the problem. I'm trying a much higher volume and a greater time length to allow it to fully clean out the engine. I want to make sure that everything that could possibly be sludged/carbonized is cleaned as much as possible.

I'm this close -->|| to taking it to the dealership, bend over in front of them, drop my pants, and telling them to fix it for me. It takes alot for me to get this close -->||.

Aside from a test drive without an exhaust hooked up, and changing my fuel filter, i'm out of ideas. My think tank (the guys at the auto-craft shop), gave up. They said it must be something Hyundai speciffic.

Please shoot me some ideas here.

alli.s007

^ ive seen you l l close a couple times before and its really not that hard to get you there. Kinda scary really, lol, but back on topic...

I know you like to fix your car yourself but sometimes it might be best to just let "them" fix it though im sure theyd do it without having to see your rosy red cheeks. If nothing youve tried is working and your think tank is depleted id go for it

DTN

^^There's a difference between what you've seen and being this close-->||. Calling the car dirty words, punching a tire and swearing up a storm is usually in the instruction manual around step eleventeen.

This is different. I'm not cursing or anything anymore, i'm just tired of working on it.

alli.s007

poor thing 02.gif *sniffles* want a cookie?

ahh i would take it to the dealer then if your tired of working on it.

DTN

^^ What? so they can hook up their expensive Hyundai diagnostics, which can do everything mine can do with the addition of ping count? Or maybe to find out it was something simple? Or how about to end up spending $1,000 in the process of them changing out the right rear tire, the passneger seat belt and the steering wheel as a part of troubleshooting?