[Mosest1]

My GF has a 01' Elantra and I can't seem to fix the sputtering. I have changed the spark plugs and oil. It overheated once and I've changed coolant and thermostat. Cleaned map and TPS sensor. Cleaned throttle body. No check engine light is on. It does it in the morning when car is cold and also on up hills. Anyone have any ideas? I also have thrown some sea foam in the gas tank... No luck. Please help.

 

[hyundaipwr]

Throwing seafoan just in the gas tank won't help all that much. The way I seafoamed my car was, 1/3 in the crank case, 1/3 in the gas tank and 1/3 gets sucked up through the PCV line.

I would check the electrical system, wires, coil pack, distributor....injectors, fuel pump.

Was the timing belt ever changed? On a car this old, if you don't know the history on the timing belt....it might be time to change it.

 

[Easy Rider]

The way I seafoamed my car was, 1/3 in the crank case, 1/3 in the gas tank and 1/3 gets sucked up through the PCV line.

Diluting your oil with ANY solvent is not a good idea.

Neither is sucking "stuff" directly into the manifold......because too much can cause hydro-lock and damage the engine.

And there are better injector cleaners than SeaForm, often at a lesser price too.

I second the suggestion that plug wires or coils might be part of the problem.

Techron, Gumout and Berrymans B12 are better injector cleaners than SeaFoam. OK to use twice the recommended amount when problems are present.

 

[DocDoug]

My GF has a 01' Elantra and I can't seem to fix the sputtering. I have changed the spark plugs and oil. It overheated once and I've changed coolant and thermostat. Cleaned map and TPS sensor. Cleaned throttle body. No check engine light is on. It does it in the morning when car is cold and also on up hills. Anyone have any ideas? I also have thrown some sea foam in the gas tank... No luck. Please help.

Accelerate HARD when it does it to force the check engine light on. Read the code and go from there.