2002 2.7t Sluggish, poor MPG, hard to start warm, rich exhaust
 

So a while back I've had some issues with my baby. Fixed a vacuum leak and wobbly pulley.
Here's my latest issue.
Recently she's been having a real rough time driving when warmed up. Step on the gas and RPMs go up, speed is WAY too slow to follow. My exhaust has a chemically smell to it (richer than I am). Noticed my MPG has taken a 10-20% hit. She'll start fine cold, but when warm it takes a few seconds to start. On a cold start the engine will shake and rumble a bit. When I stomp on the accelerator, it feels like I'm missing.
Also, I've noticed my coolant temp has started to rise when the car is parked after a drive. Never seen that before. Coolant temp is always slap in the middle while driving, but after a minute or two parked and when I start her again, the gauge will read almost 3/4 to the top.

So, what do you guys think?
In the past 4 months I've gotten:
New spark plugs
New MAF
Timing belt, serpentine belt, Pulleys, tensioner, Thermostat
Fuel injectors cleaned professionally
New Air filter
Coolant flush, oil change
I see no coolant leaks, oil leaks and hear no weird noises from engine
No CEL is on

Only thing I can think of is maybe my new thermostat is sticking, but the symptoms and the temp gauge contradict that.
or
Maybe the CTS(coolant Temp Sensor). Might explain the hard start and sluggish response.

Any input would be greatly appreciated.

Cheers!

just thinking off the top of my head, maybe o2 sensor? it would explain the sluggishness and poor mileage. i dont know about the temperature rising when in park though

Don't think it's those guys. Had the rear ones replaced a little while ago and the front ones measured good on the voltmeter.

In the past, for similar symptoms people pointed out at a plugged cat, or plugged cats. It may be worth looking into it.

EGT's can cause fueling dumping, bad EGT's rarely throw CEL's, try logging the car and measuring the EGT. When mine went bad they always measured at a constant temp, it was hard to start because it was dumping fuel to overcome a perceived rich environment

my vote is for the coolant temp sensor.

Try pulling the Vacuum line off the fuel regulator. You should not have any fuel coming out of that, If so the reg is bad. Test your fuel pressure if you have too much pressure either the Reg is bad or the return line is crimped that would dump excessive fuel into the cylinders. You should have 3.8-4.2 BAR with engine running if not replace the regulator and try again. To test the return line disconnect it from the rail take your fuel cap off and blow a little air through it you'll hear it if it's OK.

I ordered my regulators through www.partsgeek.com and they came the next morning.

The temp sending unit being bad might cause the car to run in open loop all of the time. It could be running a little rich but you would notice that the gage doesn't work.

Does your gage say Cold on startup then go to the dead middle when warm? If not it's Bad if it does it's probably good.

The coolant temp gauge used to barely get to midrange after 20 minutes of driving. Now it goes from bottom to midrange in five minutes or less. Don't think the fuel system is the culprit, but that'll be my next stop after the CTS and cats. Going to Midas later today to have the cats tested. I appreciate the help mightily. Update later today.

UPDATE:
Just came back from Midas. They did the drill test on both cats measuring pressure. Both came back reading better than factory specs. They did find that the pre-cat O2 sensor on the left bank had quite a bit of filth in it and cleaned it free of charge. Car seems to run a little better, but the stumble is still present. So I guess it's on to the CTS. Any idea where the thing is? I looky but no findy.

That didn't sound like a Cat problem. Not if it's running rich.

It takes only 1 second to pull the vac line off the fuel regulator. Give it a try. That is usually what happens when they fail.

If your temp sensor was acting up (and it wasn't 30 below outside) I would change it.

My gage reads Cold when I start it and about 4-5 minutes later it goes straight to the middle staright up and down.