1997 LeSabre, PLEASE Help, Automotive Nightmare

I just bought a 1997 LeSabre Custom. 170,000 miles. I have never owned a car with so many problems. I know very little about the car, other than the fact that it has a new fuel tank, fuel fump/sending unit, and spark plug wires. My list of problems starts here:

-At any given (random) time, when I start the car, it chugs and sputters with a very unsteady idle. Little to no engine power when this happens, and it has actually stalled out on me at a stop sign before. It could happen twice in a day or once in a month.
-Again, at any random time, when I try to start the car, it turns over, and keeps turning, and keeps turning, no fire. It will sputter as if it is about to fire. If it does manage to start up, it holds idle for 5 seconds and dies out again. Waiting 10-15 minutes usually clears it up and it could not happen again for a thousand miles.
-Other times when starting it will BARELY turn over. It will turn so slowly it sounds like it might lock up and it is not enough to start the car. A boost will start it properly. I know that my battery is good, too.
-On a cold start on a cold morning, the car will start and idle normally, but when I go into the house to let it warm up, it gradually increases idle speed, and will bring itself up between 3000 and 4000rpm. Clearly not good for the engine and a huge fuel burner.

If anyone can help me out with my problems, I would appreciate it. I am at my wit's end. I am so tired of waiting and hoping I can get to where I'm going, and even getting towed (it's happened). I just want to know if they are expensive repairs, because I don't want to put the money into this car anymore. This is not my first problematic LeSabre, but it will be my last.

Welcome to AF, a full scan would be in order to look for any skewed sensors, I would also check for raw fuel in the hose to the fuel press regulator, also see if you are loosing coolant with no visible signs of a leak.

I just bought a 1997 LeSabre Custom. 170,000 miles. I have never owned a car with so many problems. I know very little about the car, other than the fact that it has a new fuel tank, fuel fump/sending unit, and spark plug wires. My list of problems starts here:

-At any given (random) time, when I start the car, it chugs and sputters with a very unsteady idle. Little to no engine power when this happens, and it has actually stalled out on me at a stop sign before. It could happen twice in a day or once in a month.
-Again, at any random time, when I try to start the car, it turns over, and keeps turning, and keeps turning, no fire. It will sputter as if it is about to fire. If it does manage to start up, it holds idle for 5 seconds and dies out again. Waiting 10-15 minutes usually clears it up and it could not happen again for a thousand miles.
-Other times when starting it will BARELY turn over. It will turn so slowly it sounds like it might lock up and it is not enough to start the car. A boost will start it properly. I know that my battery is good, too.
-On a cold start on a cold morning, the car will start and idle normally, but when I go into the house to let it warm up, it gradually increases idle speed, and will bring itself up between 3000 and 4000rpm. Clearly not good for the engine and a huge fuel burner.

If anyone can help me out with my problems, I would appreciate it. I am at my wit's end. I am so tired of waiting and hoping I can get to where I'm going, and even getting towed (it's happened). I just want to know if they are expensive repairs, because I don't want to put the money into this car anymore. This is not my first problematic LeSabre, but it will be my last.

The slow cranking may indicate poor connection at the battery. Check all terminals for corrosion. Clean. Reseat. Check between the two positive battery cables for corrosion on the lead spacer between them. I'd even cut into the plastic covering the wires to get down a few inches along the copper to see if it's been eaten away.

High idle sounds like a vacuum leak. The unsteady idle may be the computer trying to adjust for vacuum leaking; the computer is trying to adjust the IAC to maintain the right mixture. Check all the little rubber hoses on the intake manifold. Check carefully for cracking and rot; the closer they get to the high heat of the engine the more likely they are to have deteriorated. Spray carb cleaner around the edge of the intake manifold to see if it affects the idle; you're looking for anywhere air is being sucked in that's not being expected by the calibration by the sensors.

Remove the idle air control and clean it. Remove the MAF sensor and clean it with a spray cleaner meant for sensors; inspect the two tiny wires for crud on them. I used a camel hair artist brush when I sprayed them to very lightly let the hairs on the brush help remove dirt stuck to the wires.

But first, you should check the fuel pressure with a pressure gauge, especially when it won't start. I believe in the states Autozone loans pressure gauges. Poor running after starting might be poor pressure.

Poor running also could be bad plugs. What do the plugs look like? Or a bad spark control module under the coils. Look at the connections of each coil to the spark control module and remove and clean the connection of wires into the module at the front.

You've already had the suggestion about the fuel pressure regulator check.

After the check fuel pressure with a gauge take a look at the fuel filter. They normally don't need replacement, according to the manual. But I changed mine at 90K and then when the fuel pump was replaced at 160K.