03 jag. 2.5 ...it says I have a vacum leak and I changed upper intake gaskets, changed spark plugs, fuel filter and car still runs rough. I have pwer on take off put when I press the gas pedal there is nothing there no response any ideas?

Do you have any trouble codes?

check for vacuum leaks!

Yes. But when started it will run rough and you will hear a hiss and you can locate the leak.

Could be a leak at intake or throttle body. while running spray with soapy water and look for vac leak/ suck.


Check your spark, should be strong when it jumps across to ground.

Check your fuel filter and pressure..

Clean your spark plugs

Mike

have you check converter clug and o2 sensor
vacuum leak check leak with w40 or else
rotor,cap.quality of fuel
hope it helps

check for any catalytic converter failure, check emissions first.

The upper intake plenum is leaking coolant into the cylinder heads. The head gaskets on this motor are awesome. So, chances are it's the upper intake plenum. You can check this, by removing the vacuum hose that runs between the upper plenum and the brake booster. Stick your finger in and try to touch the top of the lower intake manifold. If your finger is wet it the upper plenum. You might as well replace the lower intake gasket while you're performing this work because they are prone to failure also. Use a shop vac to pull any coolant out of the cylinder heads. Get brand new spark plugs because the old ones are probably fouled. Once you get the plenum and gaskets replaced, remove your fuel pump relay and leave the spark plugs out and turn the engine over repeatedly for about 10 seconds to push any excess coolant out of the cylinder heads. Then, put the spark plugs in and turn the engine over for 10 seconds again. This will burn excess fuel as coolant out. Then, replace the fuel pump relay to allow fuel to be pumped into the heads. Car will smoke for a few when it fires up, but will clear out quickly. CHANGE THE OIL! Twice within a week if possible.

fuel or fire its one of them replace fuel filter change plugs wires cap rotor could be a cloged fuel injector or a vacum leak good luck

the data for the code should show if the misfire is registering at idle or at a higer RPM. This is needed to know what could cause it. I hope that someone at least replaced the spark plugs so far. Next guess would be a intake gasket leak or a defective injector. If its running rough at idle start unplugging one coil or injector at a time. The engine should stumble a little if the cylinder is ok. If one does not change the idle at all then that cylinder is the one in question. Only options would be a defective injector, a defective coil, a vacuum leak on the intake, a bad spark plug, or a bad valve.

ROUGH IDLING CAN BE CAUSE BY MANY THINGS.I AM LOOKING AT LEAKING VACUUM HOSES OR INTAKE MANIFOLD GASKET LEAK.DIRTY FUEL INJECTORS AND WORN ENGINE VALVES WILL CAUSE ROUGH IDLING.ALSO LOW IDLE SPEED CAUSE ENGINE TO RUN ROUGH.

ford has a technical service bullitin out on this vehicle for the intake gaskets leaking causing a vacum leak that set codes 171 174. the solution is to have the intake manifold gaskets replaced . call your local ford dealer and see what thay can tell you about this bullitin.

did you check the timing?