03 Santa Fe, hard start, weak acceleration. Later works perfectly.

I have a 2003 Santa Fe, 6cyl, 2.7 automatic w/AWD. It has about 26,000 miles and has had all the regular maintenace done and has never given me any
problems.
Today around noon, going out to run an errand at lunch time, I turned the key and the engine cranked, but didn't start right away. Thinking I let go of the key to quick, I tried again, no luck. On the third time, I slightly pressed the accelerator and it started, but I didn't think it sounded quite right, a little rougher than normal. I stared moving and there was very little acceleration. No warning lights were lit on the dash. As I gradually got up to speed, it started sounding rougher and didn't seem to want to shift into 2nd. I used the shiftronic and it smoothed out some, but still no power. I pulled over, stopped the car and restarted it. It still needed a light touch on the gas to start it, and the weak acceleration didn't change.
I ran the errand I needed and went back to work. I called the dealer service department and he said the earliest he could get to it was Thursday. A loner car would be available for warranty work if it needed to be kept overnight, but I wouldn't be able to get the loaner until they actually worked on the car. After talking a bit he agreed that if I dropped it off Sunday night, he might be able to take a look at it on Monday.
About 6 pm I left work to go home. The car worked perfectly. Quick start without pressing the gas, normal acceleration, normal shifting, etc.
At this point I'm not going to take it in (unless it acts up again over the weekend). I don't really want to go through the trouble just to have them tell me they can't find anything wrong.
Any suggestions would be appreciated.
- Mike
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Crankshaft Position Sensor???
I know my 2002 had a recall on this and gave me problems until it was replaced.
Or it could be your transmission. When you switched to shifttronic, what gear was it in? It may have been in limp mode?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I thought about the 3rd gear "limp home" mode, but that didn't seem to be the issue. It was in first the first time I used the shifttronic; I thought the problem was that it wasn't shifting out of 1st, however it pretty much acted the same way no matter what gear it was in.
I've used it several times since, and everything seems fine.
A friend of mine said he had similar effects on car he had several years ago, and it eventually turned out to be the oxygen sensor. I was also wondering if maybe I had something wrong in the gas. I'd been getting fuel from the same place for a couple of months and haven't had any other problems, though.
- Mike O.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Based on the info, it sounds like an engine performance issue, possibly a misfire. It may be best to take it in and let them have a quick look at it. If it's running okay, and there are no trouble codes, and the find nothing wrong, then take it and be on your way. If something needs to be fixed, take the loaner and come back when it's repaired.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.