Hello .. I need some advice on what is wrong with my 1995 Chevy Blazer 4wd ..


While driving after about 20 mins the car surges like its cutting off the gas ..It will rev up and down ..It also will do this if I run the AC and the temp will go from 190 to 230 .

I have replaced Fuel pump,fuel filter,Plugs,plug wires,Dist cap. Air filter . Replace Map senser, Tps senser,Ips and clean the throttle body and the senser in the Hose entering the Throttle body.

I dont know what else it could be???

 

CMFI or CSFI fuel delivery system? Is the PCM mounted on top of the coolant reservoir on the passenger side inner fender?

 

Yes it is On top of it.

 

The parts that you replaced: what brand did you use?
Temperature rising: have you checked coolant level?
Is the fan clutch working properly, "roar" sound when cold, then gradually decrease?
Have you checked fuel pressure and leakdown?
Is the check engine light on? If so,what codes are present?

 

I used the parts that it calls for. the brand not sure ..From o'reileys .. No codes Had them check yesterday .Check engine light not on. Not sure what how to check fuel pressure or Leakdown<not sure what that is> . The Fan clutch is good and the Coolant has the green Antifreeze < Should this be Orange> since its a GM .. I replace the whole assemble on the fuel pump..

 

The parts that the vehicle calls for, are made by AC Delco. Aftermarket parts are not a good choice. These engines are very fussy when it comes to spark plugs, plug wires, distributor cap & rotor & especially fuel pumps, if you want it to perform properly. I understand that you replaced the fuel pump module, what brand was installed?

Coolant: 1995 was a transition year and it could require one or the other depending on when it was built. You'll need to check the label under the hood. If it calls for Dexcool, (orange) use it. If it calls for ethylene glycol, use it. Do not mix the two coolants.

Fuel pressure: Most auto parts stores sell/rent fuel pump pressure testers. Checking fuel pressure and leakdown will tell if the fuel delivery system can build, and hold, the necessary pressure. Key ON, engine OFF, fuel pump running, pressure must be 55psi to 61psi and must remain above 50psi for at least 10 minutes. Just because the pump is new, don't assume it's OK.