Seeking technical assistance with the Elantra

[12secondv6]

Well, the fiance has a 2002 Hyundai Elantra 4 cyl automatic

It has approx 110,000 miles.

Pre-me.... the car was unfortunately not maintained very well. Since I have come into the picture I have done a full tune up and fluid change etc and the car has been running great. Getting over 30 mpg..... running nice and smooth etc.

About 1 month ago I would notice that after driving approx 30 minutes when I would come to a stop the car would have a slight miss or run slightly rough at idle. At first I kinda dismissed it as bad gas.... maybe even fuel system needed cleaning.

I added some injector cleaner and continued driving.

Over the past month it has become worse.

I noticed that when I come to a stop and raise the rpm's to about 1,500 everything would be fine and no miss/ run rough.

At this point....NO check engine lights!

So... a week ago genie and I were cruising along the highway doing 75 ish, A/C on and going up a long hill and the car lost power and check engine light blinked a couple times. I let off the gas, moved over to the slow lane and the check engine light went out and the car was fine. This happened for a maximum of 5 seconds at best.

Today I popped off the intake and began cleaning the TB and intake manifold with both TB cleaner and also mass air flow sensor cleaner.

I drove the car a little bit later and it ran GREAT! The idle issue was gone, it felt much peppier.

After about an hour of driving around town and also sitting idling in the driveway for another hour the idle issue came back.

I let the car cool down for a while and continued to inspect/ clean the TB and intake. It was frigin black as hell in there and each time I used a rag in there it came out covered in carbon build up.

I just went for a drive and the idle issue came back and then the loss of power/ flashing check engine light came back. Shortly after (maybe 5 seconds) the check engine light went out.



What do you think it is??

I already have a suggestion of doing that sea foam stuff.
http://www.seafoamsales.com/motorTuneUpConsumer.htm

Any other suggestions? Could it be the maf?

Granted.... I have never seen such a huge amount of carbon build up in a TB n intake before....

[trashman01]

use the seafoam then make sure u aint got any vacum leaks, then pull the plugs and check them out. or get the motor nice and hot and spray intake cleaner in there. after that, witht he motor running, pour a very small amout of water(just enough to get the motor to skip a lil or just under) for a couple minz, this will steam clean the motor but dont do that last part of u dont trust urself. i have done it twice(my 92 acclaim, fixed a diseling problem) and my dads old taurus(trying to get it to run better)

[Tru2Chevy]

I would focus on figuring out why the intake/throttle body is getting all nastied up that fast....

- Justin

[GP99GT]

change the PCV? if its getting all ****** in the intake tract, sounds like oil is getting in there somehow. also, on my GP, i had a bad MAF sensor...cleaned it, ran great for a bit, then the problem came back. had to replace it

[ShitOnWheels]

He will try the water idea.

PCV was just changed about 1.5 months ago.

[GP99GT]

water idea works even better if you use a spray bottle to mist it into the intake

[heavy_chevy29]

i would say that 90% of the time the carbon build up on the tb is do to a bad pcv valve. what kind of parts did you use for all of this. did you use local parts store stuff or parts from the dealer. i ve seen people do tune ups with local parts store parts and the plugs are wrong or the wire cause a miss fire. lets face it the aftermarket stuff that is out there isnt that great. and just for ****s and giggles check your belt tension. i seen lose belts cause missing fire symtoms/codes. outside of that i would check your fuel trims if you have access to a scan tool. i would also bring it to a shop and that them to a real top end cleaner. there are pros and cons to doing this to a high mileage car.

[Savage_Messiah]

What year again? I know my dad's '01 (i think... it may be an '00) had electrical problems that Hyundai took care of (they posted a TSB and it was a free repair and all). It's something to look into.

[firehawk1120]

use a small hammer on it if that doesn't work a larger hammer might....

[j0n]

step one: plumb nitrous bottle to intact duct(no solenoids)
step two: mount nitrous bottle in passenger seat(passenger seat belt is sufficient)
step three: go wot from a dig
step four: open nitrous bottle
step five: buy another benz