Just bought my car need help

[ScottEdwards73]

So I have a 2003 Buick Park Ave Ultra, I have had it for a week it ran great the first week and all weekend drove 500 miles. Had an oil change and just turned over 200,000 miles



Monday morning I went out to start my car and it would start and rev up then die finally got it to work. Worked fine on the way home. Every day since Monday I have had issues with the car starting and the it dies I do this process for about 15 min then it stays running so I get in and drive to work sometimes on my way to work the cars rpms will tank to almost zero run rough then come back on to normal rpms. But, the traction control off light appears on the dash after an episode like this. Other times the car will be running fine 50 mph down the road and rpms will fluctuate and bottom out car dies. Other times pulling up to a stop sign car dies. Last oil change was 600 miles ago with high mileage synthetic oil. No check engine light comes on with any of this

 

[tb.dxb]

Others in the forum here have much more experience, but my first questions are:
- Is Check Engine Light on?
- If yes, can you read the codes?

If I had to wildly guess, I would suspect the Crankshaft Position Sensor. I had the same many years ago. Replaced it and everything was well again.

 

[Mgd]

It may be that your catalytic converter is clogged

 

[ulycyc]

Don't know the repair history but at 200k it may need a lot. I would start with a full tune up, plugs wires and filters. Check fuel pressure. The condition of the throttle body iac and maf. It may need major cleaning new iac and maf. As mentioned above check all that too.

 

[Smith1000]

I had a LeSabre that would die on a down hill slope when coasting and sometimes pulling up to a stop. It would always start right up again. No check engine light ever came on. I finally cleaned the MAF sensor with MAF sensor spray and it would run better for a spell. I eventually replaced the MAF sensor and that fixed it. Could be something else going on though. I would check the fuel pressure. I always just replaced the cam position and crank position sensors in the 3.8 because they were known to go bad. I had one where a wire between the ECU and ignition module went bad for some reason. I bypassed it and completed the circuit and it ran fine after that. Another thing to check is to ensure your battery terminals are clean and have good connections, including ground wires.