what's wrong with my 91 caprice?

Question

I just bought a 91 caprice (v8 - 305 motor ) for $1000, the car had been sitting over a year. When we did the test drive it did great, then on the way home the alternator went out...we replaced that with a new one and the car seemed to be doing great...The next day we drove the car all over town and it did fine, and then all of a sudden we stopped at a stoplight, after stepping on the gas the car is real choppy and ends up dying. we barely made it home and someone told me to put some fuel treatment in it, I tried that and it didnt work...someone else said it could be the catalytic converter but after taking it off the car still did the same thing. Now when I start the car it dies and runs real rough. PLEASE HELP!!

just wanted to add that we changed the fuel filter, cleaned the carb, put some heet in the gastank, changed plugs and wires and it is still doing the same thing!!!

I have changed everything but the fuel pump, hopefully it is that!

Answer 1

Sounds to me like you may have a weak fuel pump. That throttlebody set up needs 10-12psi to run properly, but they will still run (barely) on as little as 5psi. Have the pump pressure tested and replaced if bad. Also while the tank is out of the car, have the tech check the tank for sugar because it will cause the same ploblem.

Answer 2

Hello there Heather,

This is what you (or someone that knows about this) have to do:
1. Replace the spark plugs, in your case a V8 has eight, so when you go buy them you know how many you need.
2. The wiring for the sparkpluggs.
3. The fuel filter, by now it must be clogged. Some cars have them inside the gas tank, so for this make sure where your car has it, and if it is inside the gas tank don't fill up when taking it to get done.
4. Change the oil and oil filter.
5. If possible change the antifreeze coolant on the radiator.
6. Make sure all the gaskets are good, no leaks.
A car that has been sitting for at least 8 months needs most if not all of this done to work properly, not to mention to not be embarrassed in the middle of traffic. So good luck girl, sometimes buying cheap things can wind up more expensive (believe me I know about that!)

Answer 3

When car's sit for a year or longer, the gas turns to varnish in the gas tank. When that happens. No fuel treatment will help you. Because, it's not only in the tank, it's also in the lines. You will need a fuel system flush and your gas tank boiled out. After all that is done. When you put your new gas in. Then you put fuel treatment in with premium gas. Then get a engine flush done. With new oil and a good fuel system, the only thing you will need to do is. Keep up the routine maintenance.

Answer 4

If you didn't add gas yourself, drain out as much as you can. Gumout and Gunk make additives to help clear moisture and crap from the tank and lines. Change the fuel filter also (after the tank drain).

You might need a basic tuneup. Start with the plugs, if the wires are cracked or the boots gets stuck, replace them as well. Look under the distributor cap. Is it cracked, big carbon trails = replace it. Check out the rotor as well, replace if worn.

If it starts running OK, oil and oil filter need to be changed and put in an air filter. Clean out the PCV with carburator cleaner - or just replace it, they are cheap enough.

Answer 5

I'm not sure but you didn't mention changing the fuel pump. Setting for over a year is a long time.

Answer 6

Don't waste time any further. An old car parked for a long time will never be the same again. It's going to be from one problem to another.

Answer 7

Check spark plug wires, might be loose or burnt. Also check fuel filter and air filter.

Answer 8

You forgot to ground the oxy sensor wire. and the catalytic wires.
remove replace gasoline in tank

Answer 9

Check your fuel filter... when they get dirty and clog they starve the engine of fuel and it will die... sound familiar?

Answer 10

no way am i touching this one