P1361 TDC Sensor Intermittent Interruption (I got this from Engine-Light-Help.com)
TDC should mean Top Dead Center.
It is the sensor that tells the computer the #1 cylinder piston is at the very top. And therefore, fires the spark plug.
Since the maintenance done above, I believe the the timing marks for the timing belt is not lined up properly. Being off by one tooth will cause this problem.
Sounds like the fuel filter is dirty and needing to be changed. It's cheap and easy to swap out.
Code P0171 is a lean oxygen sensor code for bank 1 on your engine. Bank 1 is always the side of the engine where #1 cylider is located.
There are a couple of Technical Service Bulletins (TSB's) that may apply to your problem.
Bulletin No.: 09-06-03-004C
This bulletin covers intermittent problems due to oxidation problems in some of the wiring connectors.
Bulletin No.: 03-06-04-030G
This bulletin outlines repair proceedures for clogged or restricted fuel injectors.
The only other thing I can think of would be a vacuum leak that occurs only in cold ambient temperatures and only affects bank 1. (possible intake manifold gasket or something similar.)
Check and see if the EGR valve is leaking, to check this spray water on it at idle, if the water steams off the valve is leaking and is the source of your problem, also are you sure you hooked the new DPFE sensor up right? re-check it..
if I am not mistaken that is the code for the engine temp sensor, it kind of works as a choke, it tell the computer the ngine temp so it can lean out the fuel mix. I think the code says engine is taking too long to warm up. A faulty sensor will read -40 C all the time