I had a similar problem - car would get up to a certain RPM (sub-redline) and after that, would take ages to climb further. The problem ended up being a clogged catalytic converter. Your misfiring is probably dumped fuel into your cat, causing it to burn itself up and clog. So fix the misfire, then check the cat.

 

Thanks for everyone's help....I haven't had much time to check out the car because Im in college and I have finals this week, plus I'm going for a mountain bike trip this weekend. I'll get back to you after I check everything. Thanks again.

BTW i don't think it's my cat conveter, i just got a new one about 1 month ago, plus I don't have any good way of checking it because my whole exhaust system is welded together

 

I did finals last week. It takes about 10 seconds to open your hood and check those 2 sensors. If the MAF is on the wrong way, it takes less than 5 minutes to turn it the right way.

 

1. As everyone has stated check sensors.

2. dont mater if its a new cat sometime parts are deffective.

3. check sensors first

4. check plugs, plug wires and make sure both coil pacs are good and firing

5. check cat

good luck

 

<div class='quotetop'>QUOTE (REDZMAN @ May 4 2006, 10:37 AM) <{POST_SNAPBACK}></div><div class='quotemain'>Okay, before you do anything else, go out to your car and check these things.

1. is your MAF on the right way? Check it, double check it, triple check it, quadruple check it, then take a closeup picture of it and post it here. Your MAF sensor is the tube sensor that goes between the throttle body intake elbow and the main portion of the CAI. About 3 inches in diameter. There is an arrow on it, and it should be pointing to the rear passenger side, not to the front drivers side. GO DOUBLE CHECK THIS FIRST!

2. Go look at your TPS. It's the sensor on the side of your TB facing the front of the engine. Look at it closely, what do the words say? Dae Sung or Kiefco?

3. #1 above.

4. Check your wires and your plugs. If you are misfiring, you should be getting a Check Engine Light. Go get it scanned and post the # here. If you aren't getting one, check #1 and #2 above.

5. Check #1 above.

6. Check #1 above.</div>


My MAF is on correctly and it says kiefco.....th tps says dae sung.

 

Dae sung, eww..
To me it sounds either like a plugs/wires problem, clogged cat, or bad tps.
The fact that you just got a new hi-flow cat kind of rules out the clogged cat problem ..
I don't think it'd be your maf, if your maf was upside down the car wouldn't really be able to idle and it would be smoking and stuff running realllllly rich.
How many miles? original plugs/wires? i'd probably change those whether it's part of the problem or not.
Now, to the TPS. There is a TSB (not recall, though some dealerships will fix it for free if your lucky, but lots will refuse to also.) on dae sung tps's. they just go bad, in later years hyundai upgraded to Kefico tps's which have an o-ring in the back to keep moisture out (must have been what they thought kept killing their dae sungs). anyway, you can get a new tps from the dealer for like $150, or from korea for $45, or from MY for sale thread for $22 wink1.gif

 

I just ordered some magnecor plug wires....i'll let you know how they work when i get them. Also, what year elantra should i get a 1.8 intake cam from?

 

And why would you have your entire exhaust welded together? ever heard of flanges? lol, that was a bad move my man. Someday you're going to need to do exhaust work on it and its going to be awfully hard because you'll have to drop the rear suspension and get a hacksaw to cut it in sections (this is what I had to do because the guy who had my car before me had a rusted out "custom" exhaust which i replaced, it took forever to get that old exhaust off let me tell ya..)

For a BBTB I would suggest getting 60-65 mm, you have a fairly larger n/a setup, so you will see more gains from a bigger bore. Turbo guys use 70, light n/a guys go with 58-60. I personally have a 61mm. Do some searching before ordernig a BBTB and airram if you care about your cruise control, there is ways to keep it but it requires some modifying.

Oh yeah, and hey, try resetting your ECU (do a search for "reset ecu" to find out how)

Magnecor??
NOOOOOOOOOOOO

man you NEED to learn to search.
these are the worst, most overpriced spark plug wires that exist...
cancel your order
ASAP!
oh wait i was thinking of nology..but NGK and PRD still own magnecor tongue.gif
I'd still suggest cancelling and getting PRD or NGKs

 

Alrite, I got my plug wires today and i installed them....it doesnt misfire anymore, but my car still loses power at the same rpms i described in my earlier post....i was thinking maybe the backpressure was screwed up since I only have 1 cat converter now that i have the 4-1 header. Maybe it could be the fact that my ecu isn't upgraded for the mods i have? i'm seriously stumped....btw my high flow cat is not clogged.

Any other suggestions?

<span style="color:#CC0000">** quote removed</span>

zoned019....do you still have that keifco tps? if so lmk.

 

Have you checked MAF direction and clogged cat?

How many miles on your Tibby?