98 Buick LeSabre V6 3.8L limited.... the car has recently had a full tuneup, one of the coils replaced, oil change, and I replaced the TPS on it a few days ago. The car was still hesitating, so I cleaned out the throttle body housing and the MAF sensor as well. I waited to put it all back together until everything was nice and dry, as to not fry the MAF sensor. (they're not cheap) I took the car for a test drive after putting it all back together and now it'* bogging down when accelerating. The initial hesitation, or vibrating sensation is gone I'm just not getting any power. What else could be causing this? My first thought was that maybe the cat needs replaced, but I am no expert.

Is the check engine light lit and/or flashing? When was the last time you changed the fuel filter?

Yes, it comes and goes, flashing then on solid, then goes off and repeats itself. The fuel filter was changed about 3 or 4 weeks ago when the tuneup was done, or it was supposed to be... he took the car to someone else for the tune up, so I am not entirely positive about that. Checking on that now though. That'* an easy fix, if that'* all it is. It seems like it'* either not getting enough fuel, or an improper air to fuel ratio.

Yes, the fuel filter was changed a few weeks ago

Sounds like a plugged cat to me, I would pull the o2 sensor and do a back pressure test.

you missing any coolant? mine did that when the upper intake and lower gaskets needed done, pretty common on the 3800.

When I replaced the TPS the other day, I noticed the coolant was low, but again, the car was just put in my hands for repair. I don't have access to the gauges needed to perform a back pressure test, but I originally suspected the cat was bad. I have had to get it replaced on my last car, and recognize the feeling of no power, but this is different. It not only bogs down, it kind of sputters if that makes any sense. It'* like the car has a cold and is coughing when trying to accelerate. Although, the hotter the motor gets, the worse it gets. (also why I first thought it was a bad cat)

if the cat is bad enough to cause misfire they are normally red looking. look around the intake under the throttle body etc for coolant drips, and i think there is a date code on top some where. if it is leaking its best to do the felpro lower, aluminum elbow, dorman upper (has egr update) as well as all the gaskets and all but three injector o-rings.

https://www.gmforum.com/mechanical-1...2005-a-304071/
https://www.gmforum.com/mechanical-1...ts-l36-297702/

No coolant leaking going on.

2 things.

1. We need those active codes.

2. Not sure if your aware, but the TPS sensor must be installed correctly, otherwise, your car will experience a bogging sensation because the PCM is "seeing" air coming via the MAF, but it can't comprehend whats going on because its not seeing the TPS move.

Watch my short clip on TPS install...