JHumes

Help, my wife has a 1995 4.0 HO in a Grand Cherokee that has issues. It is hard to start when it is cold and if you wrap the motor up to 3000 RPM it coughs and misses and goes to hell. We have change MAP sensor, the crank pos. Sensor, the injectors, fuel fiter and checked the pressure which was good. I'm out of ideas. Anyone of you`ll have any other ideas or thoughts. Thank you

kjc

Basic tune-up? Plugs, wires, distributor cap 'n rotor. Maybe test the TPS and clean the IAC?

tjwalker

How does it run when the engine warms up? Important distinction.

Forgot one sensor that could be in play; the "coolant temp sensor". If the sensor has gone haywire, it will tell the computer that a vastly different fuel/air ratio is necessary.

They can be tested for resistance, but doing it the proper way is kind of a PITA with a beaker of water calibrated thermometer, etc. Most guys just swap em out as they aren't that expensive. Located on your thermostat housing.

JHumes

We did the basic tune up this last summer. I have check the burn on the plugs and they look OK.
I check the tps it was good. She told me it doesn't what temp it is.
Thank you