Starter problems-starter works fine sometimes

I would first suspect the fuel pump. Do you hear it buzz on for a couple seconds with turning the key to ON, not start?
It should come on for 2 seconds to prime the line with pressure to the engine. Do you hear it? Stand by the gas tank and have someone cycle the key to on if you need to.
If you hear nothing from the tank, you need to investigate the fuel pump and it's circuit.
There will be a fuse for the fuel pump, it is under the hood in the power distribution box-the fuse/relay block. The power for the pump goes from that fuse to the fuel pump relay (also in that fuse/block) and when the engine computer signals that relay on, the power goes through the relay and then directly to the pump in the tank.
Try this test, if your pump doesn't work-test the FPR-to test if the relay is getting a signal from the computer: hold your finger lightly on the relay. now have a helper cycle the key again from off to on (not start). Every time the key is cycled you should feel the click of the relay energizing. If you feel it click and you checked the fuse and it is good, and you still have no pump coming on, then it is likely you need a new pump. Bang on the bottom of the tank, a couple of raps, then see if pump turns on. A failing pump can sometimes be turned on by jolting it like this, but it only works a time or two or three.
So now what? If the pump is working and putting fuel to the engine, then check for spark at a spark plug. Usually a sudden no start means the engine has lost either gas or spark.

There is a chance that your pump itself is going bad. Just like a starter that is on its way out. if you tap on it sometimes the brushes will make contact enough for it to go ahead and start, a fuel pump motor has brushes and an armature. Sometimes they will not make contact and work, then other times they can run fine for a bit.

normally dont get clicking on a fuel pump normally its the starter selinoid that clicks can you hear the pump with ignition on or only when it starts i would replace the relay replaced first cheapest thing to replace first hope this helps ivan

My 94 pathfinder would start sometimes and not the other what i sis was Under the drivers seat is the security alarm the connection has 16 wires unplug it and your pathfinder will start right. I was having the same problem it would just click changed the battery the starter and the relay still doing the same researched and found that the security system is faulty I unplugged it and now my car starts every time yay much better
irine on Aug 16, 2012

If you hear relays clicking sometimes and the jeep won't start, at those times, is the check engine light illuminated on the dash, or not? If no check engine light is on the dash, at times when the jeep won't start, your ecu is in need of repairs. The ecu sends power to the ignition and fuel relays and when the ecu starts to malfunction, the relays usually start clicking.

If the pump starts to jam it wills seem like it won't run. The stuttering on startup is also related to a failing fuel pump as the intank pumps in our Jeep (I have the same ZJ)

Next time it won't start, try hitting the fuel tank with a small hammer (lighty as per not to crack it)
This can sometimes jar the pump in such a way to get the fins spinning again. If this works I would reccomend replacing the fuel pump.

You should also hear the pump prime when you turn the ignition to on (before start)
Priming the pump 3-4 times can help the stuttering on startup.

You can also get a fuel line pressure tester from most auto parts stores and verify that you are holding pressure after the pump is off.

Cheers
Dave

sounds like the fuel pump needs replacing or a in line fuel filter is stopping up.

It is most likely the Ignition switch. I have replaced several for this exact simptoms.
To check it, you test the power for the fuel pump relay.
When the ign switch starts acting up it will not power up the fuel pump relay portion of the fues box.
You can check it with a test light.
On a day when it starts and runs fine, pull the fuel pump relay, turn key on and probe the socket with test light and make note which ones have power to them.
Then one day, when it dont start, dont turn the key off yet, pull the relay, and retest, and compare.
If there is no power where there used to be power, replace the ignition switch.
Hope this helps
If it does please leave some testimony

could be the starter but could also be a relay that is not working properly. the relays are under the hood. you would have to have someone under the hood and someone turning the key at the same time to see if the relay is working. if it works every time you turn the key then its probably the starter.

change fuel filter if you have then change fuel pump