First of all, this forum has been awesome to reference for my new to me 2000 TL. Lots of little things that I knew the car needed and having this site to look stuff up is a huge help!

Bought the car about 3 weeks ago to replace a totaled car until my wife can find a job. Basically, a good daily driver for the next few months or so. I'm the third owner, the previous owner had the car for ten years and bought it from the dealer who sold it originally to the first owner. It has 193k on it and the transmission was rebuilt in October of 2015 and has seen about 10k miles since the replacement. Hopefully limiting issues with it. A/C works well and new tires, so I think it was a good buy.
Since getting it, I've done a complete brake job and bled three of the four calipers. The car spent a lot of time in Wisconsin (I'm down here in Texas) and I can't get the driver's bleed screw to break free. I'm still working on it with lots of PB Blaster to get it to loosen. I may just give up and replace the caliper, but not quite there yet.

On to my question. The car ran a little rough and my first fillup (with very grandma like around town driving) was 17 mpg. I've done the air filter, cleaned the throttle body and intake (by taking the cover off), 5 new NGK plugs (see why below) and new upstream O2 sensor. This last tank was 20 mpg (replaced the O2 about halfway through the tank) and the car seemed to run better, but still a little rough at idle with the A/C on and a little hesitant when I first start it. I've also put in a new radiator fan and temp sensor. I tried to pull the sensors from the TB to clean them, but the screws are so tight in there (with multiple bit sizes and a socket wrench) I was risking stripping them out. So, I stopped. I've also been running it with injector cleaner since I bought it.

Any recommendations on what to tackle next for the first start up stumble and 600 rpm idle?

I'll try to tackle the TB sensors again this weekend. The reason I only replaced 5 plugs is because on one of them, the end of the boot separated from the boot, itself, and is stuck on the plug. The other plugs looked fine, just not NGK's. I tried pulling it with needle nose pliers and a pick, but it just won't come off. Next step is to probably slather glue on the end of the boot and see if I can press it back in there to get it pulled. When I do, I'll replace the boot.

-Rob

 

To piggy-back off your post - can anyone give me troubleshooting tips to figure out if I need to change out my O2 sensor? Since my car is almost old enough to buy it's own drinks here in the states, I figure I should be checking just about every part for whether I should swap it out : P

I had a rough idle a bit ago, but that was resolved with a cleaning of the intake manifold, throttle body, and IACV. I then adjusted the cable since I had messed it up in the process, and ran the idle re-learn procedure. Solved that issue!

Just wondering - you're using high-octane gas in your TL, right?

 

For me, I changed it because of the mpg numbers I was getting. According to the forum, the O2 sensors get lazy. They won't throw a code, but you'll end up having rough running and burning a bunch of gas. Sounds like if you were able to get of your rough running, I need to go through a cleaning again.
Yes, I'm using premium at all the fillups based on the manual for what these cars need. Hence my watching the mpg's like a hawk.....

-Rob

 

Hmm, maybe I'll have a go at swapping my O2 sensors out then - smells like a gasoline spill when my car runs.
I used three bottles of carb cleaner and a toothbrush to clean my system out - those 19 years of never being cleaned really showed!

 

Hey Arkady, I changed my up-stream 02 sensor out, simply to see if it made any difference, in overall economy. 230K plus miles, at the time, and averaging 32.3 mpg,highway, over the same route. This past Sunday, I checked it again. 171 miles traveled, 31 around town miles, and 140 highway miles, on a 98 Deg. ambient day, with the A/C on continuously, highway speed, averaging 62-68 mph., yielded 34.683946 mpg. Whenever I test, for mpg., I attempt to include less than 20% around town driving. I'm not sure, there is a way, to test an 02 sensor, for deficiency, but I do think mpg., is a valid indicator of overall engine efficiency. .