i need help 89 caprice dies

[sugakane24]

i have a 89 chevy caprice wagon and it drives good for about 30 mins then dies then hard to start but when started it dies at 25 30 mph what is the deal?

[MagicRat]

My first guess is an bad ignition coil... it's located in the distributor cap. Often, bad ones work well enough when cold, but as they warm up from running, their performance gets progressively worse.

If you change the coil, consider changing the distributor cap and rotor, spark plugs and plug wires, if you have not already done so recently.

[maxwedge]

Also check the inlet filter in the carb fuel line fitting.

[sugakane24]

anybody

[sugakane24]

iv done all that still the same

[MagicRat]

Originally Posted by sugakane24

iv done all that still the same

Exactly what have you done?

There is no magic bullet that we can tell you about here, so please give us some more details about the work that has already been done.

Cars can fail in many different ways here, so without some more detail from you, we would end up in a lengthy, time-consuming, pointless waste of time in telling you about every possibility.

[sugakane24]

iv changed fuel filter, coil, plugs, wires, cont mod, clean the carb, new trane not sure what to do next the car sat for 7 years but runs great for a little and sounds great in park only dies when drive for 20 mins and then runs crappy till it sits for a hour im bought ready to sell it if i cant get it right iv had 43 cars and never ben stumped like this

[maxwedge]

I would check for proper fuel delivery at the carb, runs crappy isn't helping us from a distance, when it does this check for fuel pump volume at the carb.., There is a filter on the end of the pick up in the tank also, if the fuel delivery is weak and it has a known good fuel pump, then I would look there.

[sugakane24]

it has a machanical pump so there is still a fuel level sending unit in the tank then?

[j cAT]

Originally Posted by sugakane24

it has a machanical pump so there is still a fuel level sending unit in the tank then?

I agree with the fuel tank pick up screen for fuel supply as a very possible cause..since this vehicle sat for many years the tank may have to be droped and be cleaned out...

re-check the newly replaced fuel filter for debris/cut open the filter, debris is on the inside..

[rhandwor]

If it runs good until the engine warms up I would suspect an intake leak. Use carburetor cleaner and spray along the edge of the intake and anywhere else you could have an air leak. If the spray hits a leak the engine will smooth out immediately.

[sugakane24]

intake but its carb that dont make since to me

[manicmechanix]

I totally agree on checking the fuel pressure and volume too if you can, and for any vaccuum leaks. Doesn't this have a electronic feedback Quadrajet with a mixture control soleniod, and maybe an O2 sensor? Some of them have a TPS and even a map sensor etc, not really sure if you might have a problem there but sounds like it's running bad in "closed loop".

[rhandwor]

These engines are very sensitive to intake leaks. As stated EGR and needing a carburetor rebuilt is very common. We were rebuilding these carburetors in the 1990's so they do need cleaned. Also spray around the base of the carburetor a very common place for air leakage. Make sure your choke is working properly.

[manicmechanix]

Good point about the carbs needing cleaned and adjusted, and are sensitive to vaccuum leaks. Which bring up a question, does the car seem to be flooding out or more likely leaning out? And does it idle at about the right speed (idle speed, mixture and choke setting).