Help, ASAP

[grizzlybear310]

I have a 1996 With the 4.0 that has been running fine until this am.

I use it on a paper route and noticed after leaving one street going to another it had a surge to it.
Up and down the speed went.
If I showered down on it, it would bog down and then pick back up some but would want to falter a little again.
Never did quit on me but when I would start up a hill. it would seem like it was trying to run out of gas and then pick back up again.

Now, does this sound like a fuel pump trying to lay down on me, and if so, what kind of job is it to change one in a Cherokee?

Any other ideas?

Thanks in advance.
Lester

Also a side note: I am getting a faint fuel smell also if that helps any.

[capt. apathy]

I'd start with the cheapest stuff first, change the fuel filter and plug a computer reader into the diagnostic port and check to see if the readings are in a normal range from all your sensors.

if something is machanicly wrong the sensor readings can point you in the right direction. or in the case of my 89, 3 of the 4 problems I've had with it have either been bad sensors or loose or coroded conections where the sensor pplugged into the harness (so if you are getting a bad reading on a sensor unplug ig, clean the conection at the plug and try again before you waste time/money on a new sensor)

btw- many auto-parts stores will loan you a reader for just a deposit

[spooleffect]

You don't need a code reader.

Just cycle your key on, off, on ,off, on and your check engine light will flash a code. If you get a 5 5 then you have no problems with any of the computer controlled systems on the car.

[grizzlybear310]

OK, I just got back from Advance who pulled the codes off for me and it was saying "Random Misfire" which that is what it is doing.

So, I have got plugs, wires, cap, and rotor for it and see what it does now.

I will keep you informed.

Thanks guys/gals.

[capt. apathy]

the key access is great (unfortunatley my 89 doesn't store the codes so I need the reader to get at them)

one thing that won't tell you though is iff you are having a problem that will not necissarily set off an error.

I was getting horrible gas milage(11 freeway), and over-heating. plugged in the snap-on scanner and it showed a constant temp reading of 130 deg. even when at overheat.

cleaned up the conection and it started reading properly, milage went up to over 15 and it runs alot smoother.

[grizzlybear310]

Hey all, I'm back.
1996 Cherokee 2DR 4X4.

Love this Jeep, but need some input on a problem I am having.
It started the other morning.
It had been running fine up to this point.

It acted at first like it was running out of gas, but never quit.
Just bogged down real bad.

I took it to Advance Auto,(I'm cheap), to have them pull the codes on
it and it said, Random Misfire in number 6.

So, I bought all plugs/wires/cap and rotor and put on.

No good.
Next I changed fuel filter. No good.

Next I checked fuel pressure.
Key on, 44Lbs.
Running 48LBs.

Turned off motor with gauge still hooked up.

Checked in 15 minutes, still at 46Lbs. so not much of a drop.

Now this evening we were out in it doing stop and go, we run a paper
route, and it started missing and did quit once.

Started back up and run like a scalded dog.

Now I am stumped. Don't know what else to do except the pump thing.

Is it possible to change it(pump) without dropping the tank?
I noticed it came out the front of the tank instead of the top.
Also is the pressure regulator on top of the pump?
My Haynes says it is.

Sorry for all these questions, but I really need to get it fixed
cause I use it ever day.
Thanks
Lester

[grizzlybear310]

update.
I changed filter and no good. Still have the same gremlins.

Used it this am and at first ran like a champ for about an hour and then they were bacm
It started sputtering and stuff and then would straighten up for a while and then do it agin.

I am really confused at this point cause it won't do it all the time.

[grizzlybear310]

Ok, have done everything I know.
I did find out that when they put a new fuel pump in it, they did not change the pressure regulator on the pump.
Just put old regulator back on.

Could this now be the problem or could the EGR valve do the same thing?

I am really stumped on this one.

Please any feedback asap would be much appreciated.

[Tim Knapp]

My 89 cherokee was acting much the same... I replaced the CPS and that was it... Mine ran fine until the temp got up to 195, then would cut out / stall and just run really rough till it was cold again. Try the Crank Position Sensor (CPS) 42.95 - Good luck

[grizzlybear310]

Thanks Tim, I will look into that.

[Tim Knapp]

It could also be the Fuel relay just behind the battery (a set of four relays) or the TPS - Throttle position sensor... located in the front of the air cleaner snorkel...

[grizzlybear310]

Thanks again Tim, but what I can't figure out is that I use this Jeep the same way ever day running 90 miles ever day and sometimes it will go 2 or 3 days without a problem.
That is what has me stumped about it.