I have a 91 C4 with an automatic trans and I can drive it for about 7 - 10 miles and then the motor starts to lose power and quit running. Alsothe temp guage increases to max hot after a few minutes. The radiator does not seem to be overheating and there is no water loss or pressure when I release the radiator cap. I can let it set for awhile and it will drive again for a short distance and then it starts to have the same symptoms. The fuel pressure appears to be within the specs. Any suggestions would be appreciated.

Thanks

 

If not for the temp I would say clogged catalytic converter. But I suppose the temp could be a symptom as well. Back pressure and all holding the heat in the heads.Some one else with more knowledge will surly answer. Hang in there.Welcome to the site as well. Cheers

 

Welcome there, '91...

What have you done to the motor lately?

This start all of a sudden?

Does it do it in the driveway? Try it, and turn the heat on max, and watch the guage, and keep yer paw on the vent to see if the temp of the air is exactly as the needle - better yet, use a thermometer IN THE VENT, and compare...

 

I am with BlueShark. It sounds like a cat to me also.

 

Odd symptoms, as far as the overheating, is the cooling fan coming on?? It could be the thermostat may not be opening, but I don't understand why you don't have any pressure on the radiator when you remove the cap in either case. Bad temp sending unit maybe? I'm not saying any of these things are your problem, I'm just throwing things at you to check.

You can try this little trick to rule out a fuel problem. You'll need a fuel pressure guage with a hose long enough to reach out from under the hood so you can strap it to a wiper blade, or tape it to the windshield, youwant to be able towatchthe guagewhile you're driving the car, see what the pressure looks like when the car starts acting up. You could have a fuel pump thats going south. Fuel filter? just because you have static pressure on the fuel rail, doesn't mean you have enough fuel flow.

Check these few things and let us know what you find, If they don't solve your problem, we'll try something else.

 

Yep...was just thinking the same thing too, he should be able to listen to the exhaust and see if it sounds different than what it usually does, especially if it's stopped up enough to stall the engine. We had an old Chevy once, and inner wall of the exhaust pipe collapsed and it sounded like a jet taking off.

 

One way to test for cat problem is to hook a vacuum gauge to the intake. Take a reading at idle then raise engine rpm to 2000 rpm. If no exhaust restriction, then the vacuum reading should be approximately the same at 2000 as at idle.

 

Hmmm...Thanks mech, I learn something everyday around here.