The car starts and runs fine,the hesitation starts on pulling away and is very bad if trying to hold a constant speed, if you accelerate the hesitation goes completly? until you return to a constant speed again. this vehicle has had a fuel pump and relay about a year ago,and recently had distributer cap,rotor arm,leads, and spark plugs fitted.any help you could give with this would be greatly appreciated. many thanks Roy.
Have you tried cleaning the inlet jets with a fuel additive
SOURCE: 2002 Jaguar S-Type 4.0
this is a old model and it should have a cold start valve or it should have a coolant temp sensor, replace the colant temp sensor which is usualy located on the thermostat housing or on the intake manifold and this will sove the clod start problema!!
SOURCE: 1989 jaguar xjs v12 fuel mixture
Chances are the coolant temperature sensor or its wiring have failed, or the vacuum line to the MAP sensor is leaky or broken (I believe the V12 in '89 guise uses MAP sensors). The MAP sensor measures Manifold Absolute Pressure. Along with this pressure the ECU looks at engine RPM. It also measures air temperature. Knowing pressure and temperature we know density, and knowing engine speed tells us how much volume of air is going through the engine. All of this together is computed into air mass and is used to calculate how much fuel mass should be admitted. If the vacuum line is broken, the ECU reads less vacuum and produces rich mixture thinking that the engine is under high load.
SOURCE: mass air meter not reading vane postion
hey rob_andersen,
yes their is a way to replace the mass air flow. Get a can of brake clean or throttle cleaner, throttle cleaner is going to work best. remove the until and spray it down with throttle clean, let it dry for about 15 min. and reinstall it.
Now a little warning for you, IF their is no visual damage to the mass air flow then you can do this successfully. Now the reason why I always replace them instead of spraying them down is because is MOST cases the mass air flow will start acting up again. Sometimes it takes a weeks, sometimes months, sometimes years its hard to say.
But the worst you have to loose, is it doenst work an your out 5 bucks for the can of fluid.
SOURCE: 1988 Jaguar XJ6 S-LINE 4.0L V-6
Fuel pump is bad or plugged fuel filter it seems. Crack the line from the filter leading towards the engine first. If gas starts squirting out fast, you have good pressue. If not the filter is plugged or a bad pump. How old is the fuel filter by chance? If original its plugged up by now
SOURCE: 1995 jaguar xj6 stalls once you stop at the stop signs
Look for an IAC sensor (motor) Idle Air Control.
Usually located on side & front of throttle body. Not 100% sure which type you'll have but if you have pintle type (pointed end) Remove it, spray it well with throttle body cleaner as well as port it came from, and retry. If it cures it temporarily & starts to do it again, replace it.
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