Thread: Troubleshooting. Where to start?

I recently purchased a 1995 grand prix with 182,000 miles and it's been nothing but trouble. When I bought it, the car had an intake manifold leak. I took it in and had the gaskets replaced as well as a few minor things that were easy to replace when the car was opened up. Other things that I have replaced on my own include; battery, alternator, plugs and wires, air filter, oil change and filter.

The issues I've been having with the car are really irregular. Sometimes the engine will start fine and the car will idle fine. Other times the car will start and idle rough and after a while it will stall out. And sometimes it will crank hard but not start. I guess I'm wondering where to start troubleshooting and if anyone has any input on what potential problems I have.

For a little more background here's a paraphrased story of what has happened:

Got the car and drove it home. Ran a little rough, but didn't die. Took it to town the next day (5 mile drive) and it died. Replaced the battery and the problems went away. Decided to replace the spark plugs, wires, and air filter, and do an oil change too. Drove it for a day and relized it was leaking a lot of coolant. Had my mechanic fix the intake manifold leak. Driving to work the next week I noticed it was running rough and would stall out when I was waiting for stop lights. Also it felt like it was slipping or missing when I tried accelerating between 50 and 60mph. Finally, it died one night and I replaced the alternator. Tried running it after that and it would crank but wouldn't start. Tracked down a fuel injector fuse that was blown. Replaced that and the car turned right over, but began smoking a little from what I believe was the cam position sensor wires. Ran it for a few days with no problems. Last weekend replaced all brakes and rotors. Went to check the brakes and the car was idling and running rough. It died on me several times before I could get it back home. Went to start it in the garage and it would crank but wouldn't start. Left it for the night and tried again the next day. It started right up, let it idle for 4 minutes before it started sort of pulsing and it died again.

That's where I'm at with it. I can't drive it to a shop and I can't afford to tow it so I'm trying to figure it out on my own. Sorry for the novel, but I figured it'd be helpful. Thanks in advance!

Thanks for the suggestions. I'll check everything out and get back to you.

Update:

Replaced the cam position sensor today which turned out to be FRIED. Car ran pretty solid and I took it out for a drive. The car seems to drive great and the only problem I have now is that the car still idles a little rough. However, it didn't die.

Tried to replace the fuel filter but the nuts were rusted shut on the filter so I didn't bother with it.

So not sure where to go from here but we're making progress. Any suggestions are greatly appreciated.

Today I went ahead and cleaned as much of the throttle body as I could without unbolting it and having to mess with the gasket. Took the IAC off, tested and cleaned it.

Found a tube, coming off the top of the air intake tube, that runs back under the ignition coil modules and into the engine block. Not sure what it is or what it's function is but it was cracked and the rubber connector at the engine block was all jacked up. I might post some pictures later.

Anyway, got it all back together and took it out for a drive. It's running like a champ, but it still idles rough. I can accelerate from any gear/speed and it's flawless but when it drops down to idle it flutters around 1k rpm. It feels like it is gonna stall out but I stopped for a minute or two a few times and let it sit and idle in the driveway for 5 minutes and it never died. Also, when I change gear, i.e. reverse, drive, etc. the rev's drop below 1k pretty hard.

Now that it's running, I'll probably take it to Advance and have them run the codes.