Ok I have searched and searched and still cant figure this out. My 01 XJ is really hard to start and I usually have to pump the gas to get it to start. My check engine light keeps coming on and reads cyl 1 misfire cyl 5 or random cyl misfire. I read on here that the coil pack could be the problem so I replaced it with a new one and got nothing. Still hard to start and engine light still comes on. Then I read that the crank position sensor could be the problem. So I replaced that too and still no results. I cant keep throwing money into this and not fixing the problem. could it be the fuel pump or injectors causing this and if so how do I check those without just replacing them first?

 

What did the plugs look like? Gapped OK?

 

You really need to read the threads better ,and buy a manual for your xj.Need more info to try and help you out also.when is it hard to start hot cold always ,after you drive it. Also dont use the gas peddle when the key is on your just dumping gas in the motor which will make it harder to start too.If you need to depress the pedal only do it when key is off press to floor than turn key, and you only do this if the motor is already flooded.

 

I replaced the plugs before I replaced the coil rail. The old plugs were shot (gapped .050-.060). New plugs were gapped .035. I thought the new plugs would help but there was no change. It is always hard to start no matter if it is hot or cold. The only time it will start right up is if I shut it off and start it right back up. If I wait 5 min it will crank for awhile before it finally starts. It also seems to run rough for a few seconds when it does start almost like not all the cylinders are firing.

 

Try turning the ign. on for a few seconds, off, then on for a few seconds, a few times, then try it. Might be that it's not holding fuel pressure and needs to prime every time you start it. I'm not any help with those codes...yet!

 

Having to "tip in the throttle" to start the engine is often a sign of a failing throttle position sensor. Test and or replace it.

Fuel pressure is easily tested with a pressure gauge installed on the schrader valve located on the fuel rail under the hood. For yours, you should see a pretty solid 49 psi at idle, plus or minus 5 psi.

 

My 2000 had a misfire, throwing codes after I replaced the plugs.
Checked all the usual suspects. Nothing.
Checked the plugs to the injectors. Surprise!
Firmly re-connected the plug onto the injector, no more misfire.