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1997 Hyundai Elantra Loss of power, gas mileage, surge, Mis

Tiny
MATTSTERCRAFT
  • MEMBER
  • 1997 HYUNDAI ELANTRA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 128,000 MILES
Car starts and idles fine. Loss of power when accelerating or climing a hill etc. Seems to re-gain power when I put the accelerator to the floor but really surges. Pops periodically when I first accelerate. Gas mileage appears to be really bad. I have a flashing check engine light which would indicate a misfire according to my manual. I have changed the fuel filter and checked/cleaned my injectors with a reputable shop. Not sure where to go next and would like your thoughts. Thanks!
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Monday, March 1st, 2010 AT 3:46 PM

15 Replies

Tiny
SCOTTY DEE
  • MECHANIC
  • 592 POSTS
Hey Matt, oh no! You did a good job giving me symptoms. The bad news is, when the check engine light comes on and flashes, it also means that conditions are present to damage the catalytic convertor. What is going to help us now, is to get the codes retrieved so we can make a plan of attack.

You could go by just about any parts store and they'll retrieve the codes for you usually for free. Write down the codes numbers, don't worry about the descriptions. We'll go from there.
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Monday, March 1st, 2010 AT 4:02 PM
Tiny
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Just had it plugged in and it read cyl one misfire. I failed to mention earlier that I also replaced all my plugs
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Monday, March 1st, 2010 AT 4:53 PM
Tiny
SCOTTY DEE
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Cylinder one missfire and no other codes present? It does have NGK or Denso spark plugs in it, yes? Do you have a volt meter so we can test the resistance on the number one ignition cable? If that checks out okay then I would start by pulling off the valve cover and check the valve train parts on number one especially.

Can you do that?
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Monday, March 1st, 2010 AT 5:28 PM
Tiny
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  • 10 POSTS
Not exactly sure what you are referring to but I have a friend that might know and I can use a volt meter. One thing to mention. At idle we pulled each spark plug wire one at a time. In each case we could hear the change when the wire was removed. So it seems as tho each plug is sparking. Not sure on the plug brand. Just looked it up in the book and bought the recommended plugs
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Monday, March 1st, 2010 AT 5:42 PM
Tiny
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If you're sure the secondary ignition is up to par, then it's time to pull the valve cover and get a look.
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Monday, March 1st, 2010 AT 5:48 PM
Tiny
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  • 10 POSTS
Ok. How hard of a job is that? And what am I looking for?
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Monday, March 1st, 2010 AT 6:01 PM
Tiny
SCOTTY DEE
  • MECHANIC
  • 592 POSTS
Childs play I would call it. It's the cover on top of the cylinder head. If it's a cork gasket, get a replacement gasket. Once you pull the cover, you'll see all the rocker arms and springs. We want to check the rocker arms for looseness, and the spings for breaks or fatigue. Would your tech buddy be able to help out a little?
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Monday, March 1st, 2010 AT 6:11 PM
Tiny
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Ok we'll try that. Just one more thing. I'm still convinced that it isn't a faulty injector. If I swap two injectors and then it reads another cylinder misfire. Can I then assume its a bad injector? Also, really dumb question but is my #1 cylinder the first on the left as you are looking at the engine? Thanks for you help
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Monday, March 1st, 2010 AT 6:20 PM
Tiny
SCOTTY DEE
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You are correct about the injector. Yes, number one is on the far left, the farthest cylinder from the coil pack. Did you give feedback? If not do so! :)

Keep me posted
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Monday, March 1st, 2010 AT 6:37 PM
Tiny
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I assume that the coil pack has been ruled out?
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Monday, March 1st, 2010 AT 6:39 PM
Tiny
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I have not considered the coil pack. Is there a way to test it to see if its weak or bad?
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Tuesday, March 2nd, 2010 AT 12:46 PM
Tiny
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  • MECHANIC
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Remove one spark plug wire from its plug, then remove the spark plug using a spark plug socket. Next put the spark plug back into the spark plug wire. Be careful not to let anything drop into the empty spark plug hole. Holding the plug wire with insulated pliers, find a spot on the engine that is a good and easily accessible grounding point. Pretty much any exposed metal, including the engine itself, will do.

Holding the spark plug wire with your pliers, touch the threaded portion of the spark plug to the grounding point. Have somebody crank the engine with the key, and look for a bright blue spark to jump across the spark plug gap. If you see a nice, bright spark (clearly visible in daylight) your coil is doing its job.
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Tuesday, March 2nd, 2010 AT 12:51 PM
Tiny
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Checked the spark. Seemed to be a little weak. Looked white not blue. The plug looked pretty black. Checked the other plugs and they were clean and dry. I did start this process with new plugs.
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Thursday, March 4th, 2010 AT 3:23 PM
Tiny
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Get a coil pack.
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Friday, March 5th, 2010 AT 9:16 AM
Tiny
EZPIMPINYA
  • MEMBER
  • 7 POSTS
I am having the same type of problem. Just curious if you bought a coil pack and whether or not it worked?
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Wednesday, April 14th, 2010 AT 2:53 AM

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