Ok so my 94' Grand Cherokee, 4.0, took a crap on me one day about a month ago when I stopped to get gas, granted that it had been out in the sun all day while I was at work and yes this is Phoenix so it's hot as sin but I got it home and have since changed the oil, sparkplugs, fuel filter, crankshaft position sensor, spark plug wires, and ran a can of sea foam through it, right now it has plenty of spark and will crank for ever but just wont fire unless I put my foot all the way in the gas while I'm tryin to start it. Among other things, my last train of thought was a faulty spark plug wire and so upon replacing them tonight, it is still doing the same thing, I am thinking now that perhaps if one or a few of the wires were bad then maybe a few of the plugs are fouled and I am going to clean them out tomorrow night and see if that helps. Another thing is that when it is running and I take it out for a cruise, If I step on the gas all the way it has quite a bit of lag before kicking in the fuel. I am at about a 40% knowledge base when it comes to engines and I would appreciate any suggestions from those out there who are more knowledgable than I, the only thing I can think to do now is clean the possibly fouled plugs and maybe change the cap and rotor. Let me know what you guys think, perhaps a timing issue? Fuel delivery problem? I'm frustrated and my lack of proper knowledge is getting the best of me. Thanks for any and all help you guys can provide.

 

chek fuel pressure

 

You should check the pressure at the rail (rent a gauge from the parts store). It could be not getting enough gas, rthat could be pressure or maybe even a pump is going bad. When you turn the key do you here the pump at all?

Also the cam shaft sensor could be fouled, so check and clean that. But I'm leaning towards a pump that is starting to show signs of wear.

 

I was also thinking that it might be a problem with the fuel pump but I was hoping that it might be something else due to the cost and hassle of replacing the pump. I also do not hear the fuel pump priming when I turn the key but I don't think that I ever have before the onset of my problems. If I get the gauge to check to fuel pressure, how do I go about doing so? and if there isn't enough pressure, what does that indicate? thanks for the replies.

 

PM me your e-mail and I can send you the information you need. I cant post it to the forum due to copy right stuff