2003 Hyundai Tiburon

Engine Mechanical problem
2003 Hyundai Tiburon 4 cyl Two Wheel Drive Manual 35,000 miles

Ok well as bad as it sounds, I don't think it is. The car runs fine until this starts happening but then it won't stop til you are at your destination. It usually starts when I hit a bump or have been driving for over 20 minutes. What I mean by shuddering and jumping is basically the car seems like it starts to hesitate, no not like its misfiring, but more so like someone is letting off the gas and punching it again really fast. What I really don't get is sometimes I will put the clutch in to stop at a red light and the engine just stalls out however 90% of the time, the engine acts 100% fine. Another thing its doing is when driving down the highway or down any road for that matter, I will let off the gas to just maintain speed and my check engine light comes on while the engine is decreasing speed. Now. The car basically felt like it stalled but the car is still running. However in order to get going again I have to basically press, well not basically I do have to press the accelerator all the way to the floor and then boom the car basically jumps back to life and the check engine light goes off. The last piece of information I can think to give you is sometimes when its acting really bad I have popped the hood before turning the car off to take a look around the engine bay. MY first thought was it could be a loose ground somewhere, however that doesn't seem to be the case on the top of the engine anyways, battery, and IM. But the catch here is sometimes when I goto shut the hood. As I do so, it stalls the car out from the hood shutting. Weird huh?

Hopefully someone can give me some insight to this as I am completely stumped and can't seem to figure out whats wrong, think it could be a ground on the underside, think there is one near the tranny? Not quite sure honestly. Checked the spark plugs but they are brand new thanks to bluegtv6 and the wires are brand new as well from NGK. However the coil I believe is still stock.

I am running in a 03 i4 turbo (System Upgrade Turbo Kit Stage 2) just to let you know but I have a feeling my mods have nothing to do with the problem on hand here.

Thanks for the help in advance,

October 27, 2010.

Tim: It does sound electrical based on the fact that it shuts when you close the hood. Have you checked grounds? The one going to the engine block? Also, have you checked connections to the PCM?

After thought. Have you had the computer scanned since the check engine light has come on?

Yes I have but never with any codes. Its like the CEL only comes on because the car basically feels turned off while deceleration til you punch the gas and then it basically feels like it kicks back into great and resumes as normal.

Oct 27, 2010.
I need you to check the crank shaft sensor to make sure the wiring is in good condition as well as the wiring harness to the PCM. Make sure things are in good condition, not corroded, and none of the pins are bent or pushed in.

Also, check for vacuum leaks and the idle air control valve.

Let me know what you find.

I went out to check what I could of your ideas to fix this and I was under the hood checking pretty much everything I could from the alternator wires to the maf sensor to the IM ground to the battery ground. Couldnt find the engine block ground. Figured its on the bottom end somewhere. But when I went to start the ar to listen to it run and maybe figure something out that way.

I turned the key into the on posistion and the radio came on like normal. But only for 2 seconds, then it went off for a second then back on for 2 then off for 1 then back on for 2 then off for 1. You get the idea. So now I am worried that its electrical. BUT it could be a good thing to be able to help narrow down what the actual problem is. Any ideas? I know this could still be the result of a bad ground but its just the radio doing this and not the lights on the car along with all the other electronics. So confused.

Oct 28, 2010.