Looking for some pointers on where to look to cure my 2.4 L santa fe's running problem. Under load and on heavy throttle openings the cars bogs down and loses power. Similarly in a high gear going up hill etc.

Starts andrevs fine, if you drive it like an old lady with slow light throttle openings you can drive round the problem but floor it and it hesitates and loses power till you back off and slowly re apply the gas.

There are no fault codes registering and the engine check light behaves as it should.

No obvious air leaks, dirty fuel etc

help !

 

Model year? Mileage? Did this just start?

 

If there's no trouble codes, then it sounds like fuel starvation.

 

Thanks for the thoughts.

Its 2001 2.4L manual, done around 70K miles serviced last summer. (Though not sure about the fuel filter, would that be a good / easy cheapfirst check. ) If so where is it ?

 

Fuel filter is probably a good place to start, but no guarantees. The correct test is to do a fuel pressure test:

2001 > G 2.4 DOHC > Fuel System FUEL PRESSURE TEST (2.4 DOHC)1.Reduce the internal pressure of the fuel pipes and hoses by the following procedures.[/align]a.Open the trunk door and disconnect the fuel pump harness connector in the trunk room.[/align]b.Start the engine and after it stalls, turn the ignition switch to the OFF position.[/align]c.Disconnect the battery negative (-) terminal.[/align]d.Connect the fuel pump harness connector.[/align]2.Remove the bolt connecting the fuel line to the fuel delivery pipe.[/align]Cover the hose connection with a shop towel to prevent splashing of fuel caused by fuel residual pressure in the fuel line.[/align]3.Using the fuel pressure gauge adapter, install the fuel-pressure gauge to the fuel pressure gauge adapter. Tighten the bolt to the specified torque.[/align]4.Connect the battery's negative (-) terminal.[/align]5.Apply battery voltage to the terminal for the pump drive and activate the fuel pump: then, with fuel pressure applied, check that there is no fuel leakage from the pressure gauge or connection part.[/align]6.Start and run the engine at curb idle speed.[/align]7.Disconnect the vacuum hose from the pressure regulator, and plug the hose end. Measure the fuel pressure at idle.[/align]8.Measure the fuel pressure when the vacuum hose is connected to the pressure regulator.[/align]9.If the results of the measurements made in steps (7) and (8) are not within the standard value, use the table below to determine the probable cause, and make the necessary repairs.[/align]Condition[/align]Probable cause[/align]Remedy[/align]Fuel pressure is too low[/align]a.Clogged fuel filter[/align]b.Fuel leakage to the return side, caused by poor seating of the fuel-pressure regulator[/align]a.Replace fuel filter[/align]b.Replace fuel pressure regulator[/align]
a.Low discharge pressure of the fuel pump[/align]a.Check the in-tank fuel hose for lage or replace the fuel pump[/align]Fuel pressure is too high[/align]a.Sticking fuel-pressure regulator[/align]b.Clogged or bent fuel return hose or pipe[/align]a.Replace fuel pressure regulator[/align]b.Repair or replace hose or pipe[/align]There is no difference in fuel pressure when the vacuum hose is connected and when it is not.[/align]a.Clogging, or damaged vacuum hose or the nipple[/align]b.Sticking or poor seating of the fuel pressure regulator[/align]a.Repair or replace the vacuum hose or the nipple[/align]b.Repair or replace hose or pipe[/align]10.Stop the engine and check for a change in the fuel pressure gauge reading, which should hold for approximately 5 minutes, If the gauge indication drops, observe the rate of drop. Determine and remove the causes according to the following table.[/align]Condition[/align]Probable cause[/align]Remedy[/align]Fuel pressure drops slowly after engine is stopped[/align]a.Injector leakage[/align]a.Replace injector[/align]Fuel pressure drops immediately after engine is stopped[/align]a.The check valve within the fuel pump is open[/align]a.Replace fuel pump[/align]11.Reduce the pressure in the fuel line.[/align]12.Disconnect the hose and the gauge.[/align]Cover the hose connection with a shop towel to prevent splashing of fuel caused by fuel residual pressure in the fuel line.[/align]13.Replace the O-ring of the end of the hose.[/align]14.Connect the fuel hose to the delivery pipe and tighten with the specified.[/align]15.Check for fuel leakage.[/align] [/align] findme('); findme('); findme(');

Looks like the fuel filter is underneath the car near the fuel tank.

2001 > G 2.4 DOHC > Fuel System FUEL FILTER REPLACEMENT (2.4 DOHC)1.Reduce the internal pressure of the fuel lines and hoses and perform the following operations.[/align]a.Disconnect the fuel pump harness connector in the trunk room.[/align]b.Start the engine and, after it stops, turn the ignition switch to OFF.[/align]c.Disconnect the battery negative (-) terminal.[/align]d.Connect the fuel pump harness connector.[/align]2.Remove the two fitting nuts while holding the fuel filter nuts securely.[/align]3.Remove the fuel filter mounting bolts, and then remove the fuel filter from the fuel filter clamp.[/align] [/align] findme('); findme('); findme(');

Another possiblility is the exhaust camshaft coming out of time. Have you replaced the timing belt? Here is the TSB:

2001 SONATA/SANTA FE 2.4L ENGINE RUNS ROUGH, IDLES ROUGH, DTC P0335[/align]DESCRIPTION:[/align]Some 2001 MY 2.4L Sonata and Santa Fe vehicles, customers may complain of one or more of the following conditions:[/align]Rough running.[/ul]Rough idle.[/ul]Lack of power at low rpm.[/ul]Check engine light on (DTC P0335 crankshaft position sensor malfunction).[/ul]This condition may be caused by the exhaust camshaft coming out of time.[/align]A new timing belt cover P/N 21360-38214-D that incorporates a timing belt guide has been installed on vehicles produced since January 30, 2001.[/align]Vehicles that experience the condition described above should be updated with the new timing belt cover[/align][/align]INSPECTION:[/align]Inspect the production date of the vehicle. Vehicles produced on or after January 30, 2001 are not affected by this TSB.[/ul]Remove the upper timing belt cover.[/ul]Rotate the crankshaft until the timing mark of the intake cam sprocket is aligned with the timing mark on the rocker cover.[/ul]Inspect the alignment of the timing mark on the exhaust cam sprocket with the timing mark on the rocker cover:If the exhaust timing mark is properly timed, skip to step 13.[/align][/ul]If the exhaust timing mark is NOT TIMED properly, continue to the service procedure section.[/align][/ul][/ul]SERVICE PROCEDURE:[/align]Remove the right front wheel and engine splash shields.[/ul]Lower the vehicle and support the engine with a floor jack.[/ul]Remove the right side engine mount, water pump pulley, accessory drive belts, and lower timing belt cover.[/ul]Set the engine to top dead center (TDC) and set the intake and exhaust cam sprockets on their timing marks (as close as possible).[/ul]Remove the auto tensioner and timing belt.Inspect the timing belt. If its worn, cracked or frayed, replace it.[/align][/ul]Inspect the tensioner. If its leaking fluid, replace it.[/align][/ul][/ul]Slowly compress the tensioner in a vise (apply pressure until resistance is felt, allow tensioner to compress, then apply more pressure) until the locking pin can be re-installed. A locking pin is supplied with a new tensioner. If an extra locking pin is not available, a 3/64" steel pin can be substituted.[/ul]Install cam sprocket holder (SPX/Kent-Moore P/N 09231-38000) to hold the cam sprockets in alignment during timing belt installation. Install the tool 1/4" deep after the sprocket timing marks are in alignment.NOTE[/align]Insert the tool only 1/4" to make it easier to remove after the timing belt is installed.
[/align][/align][/ul]Verify the following timing marks are aligned (refer to photos below):Camshaft sprockets (intake 1, 2; exhaust 3, 4)[/align][/ul]Balance shaft (5, 6) and oil pump sprocket/balance shaft (7, 8)[/align][/ul]Crankshaft (9, 10)[/align][/ul][/align][/ul]Wrap the timing belt in a clockwise direction starting from the intake cam sprocket. Keep the belt tight when installing over the exhaust cam sprocket, oil pump sprocket/ balancer, and crankshaft.[/ul]Apply hand pressure to the tensioner pulley to take up any slack, and remove the lock pin from the tensioner. Remove cam sprocket holder.[/ul]Rotate the crankshaft clockwise (by hand) 2 complete revolutions and set to TDC. If the TDC mark was passed, then rotate the crankshaft another two complete revolutions. The crankshaft must only be turned clockwise for proper tension and orientation of the timing marks.[/align][/ul]Inspect the timing marks of the cam sprockets for proper timing.NOTE[/align]Due to the difference in ratio between the crank sprocket and the oil pump sprocket, the oil pump sprocket will appear out of time after turning the crankshaft 2 revolutions (provided the sprocket was set properly in steps 8 and 9). The oil pump sprocket will come into alignment on the 6th revolution (1 : 1.5 ratio; crank to oil pump).
[/align][/align][/ul]If the timing marks are properly timed, rotate the crankshaft an additional 90 degrees to take the marks off of TDC.[/ul]Reassemble the engine (if applicable) and install new timing belt cover P/N 21360-38214-D.[/ul]WARRANTY INFORMATION:[/align]OP CODE[/align]OPERATION[/align]OP. TIME[/align]OP. QTY[/align]NATURE CODE[/align]CAUSE CODE[/align]21361R00
Timing Belt Cover Replacement
0.2
1
N02
C24
24312R00
Timing Belt Replacement
1.7
1
N02
C10
[/align][/align][/align][/align]

 

Worth noting:
Another real possibility is that one or both Catalytic Converters are failing and restricting air flow. This will result in a major loss of power when under load to be followed by a drastic drop in fuel economy. 10 miles per gallon or so.

 

Our '03 Santa Fe has the identical problem. So far, we replace the cam and crank sensors, the fuel filter and fuel pump, and spark plugs. The problem seems less pronounced and we're still chasing the problem. Also but probably unrelated, our factory stereo turns on by itself and when listening to radio, will switch to CD mode on its own. Will give an update once we find the solution to problem(s). Any input would be greatly appreciated!

 

Im haveing same problem with my 2006 sonata...while driving fine it seems to just go into ..a no fuel mode for about 30 seconds or so and then resume, driving fine...it did it yesterday so I pulled over and put it in park stepped on the gas pedal and it just continued to idle.....no rev at all...then when I put it back in drive it got me home fine....driving normal..??????any ideas....

 

if the cat converter were junk, wouldnt it throw a cel? i hooked a reader up to it and no code present. problem still exists today. no idea.

 

Mine at 72K miles had the same problem. No codes present. Try the cat converter the one right off the exhaust manifold then the other which is in line prior to exhaust muffler. Both are expensive if you live in California. The first is $800.00 at the dealer, however its easy to install, bolts right up. The second needs to be welded in but easy installation at a muffler shop. Also expensive because Calif EPA added additional manufacturing requirements and restrictions as of Jan 2008 which must be licensed and approved by Calif EPA, the tightest in the nation. Each cat must be metal stamped and embossed with the Calif issued and approved serial number. Good news however. If you live in the other state you can buy both of these cats locally or on ebay that will bolt on to your car for half the price or less.
Also worthy to note: In Calif if you buy it from dealer it is considered an OEM replacement part and does not have a Calif embossed serial no. So, if you buy it on ebay and the source agrees to ship it to you, who's to say it isn't an OEM part. Once installed its grandfathered in. Same as if you bought it from the dealer.
So, go figure.
P.S. I'd replace the first because that's the one that heats up the most and fuses the pellets inside the Cat thereby restricting the exhaust flow. If that doesn't fix it, then the second. Seldom do both fail at the same time.
Hope this helps !