I have a 1996 Cherokee sport with 240000 miles. no major modifications done under the hood, except new water pump and radiator, plugs, wires, cap, rotor. The basic maintenance.


So here are my issues


Maybe 25% of the time, I will start the jeep and make it out of the parking lot and give it some gas. Then it kind of bogs down for just long enough to be concerned when there is traffic coming. about 3-5 seconds, it will just slow down almost like it is dying but it has never died. then its all fine and dandy and I wont have any issues the rest of the day. It does it after sitting all night or just a couple hours after sitting at work. Any ideas on this one? I have a couple thoughts. It has a newer fuel filter it. About 6 months old.


Next issue, and I believe it is completely unrelated. In the mornings after sitting all night it will make a noticeable noise when turning. Not really a grinding more of a loud hum, or some where in between. It only lasts 1 or 2 minutes then its gone the rest of the day usually unless I work a 10 or 12 then sometimes it comes back.


Thank you for your wisdom

 

the first issue could be your TPS or IAC valve. both are right next to each other on the throttle body.

the hum could be from your power steering pump starting to go out. and is humming till its fully warmed up.

 

First could be a weak fuel pump. Second probably is a weak power steering pump.

 

If it was a fuel pump it would continue to act up through out the day

 

Not true. I just replaced a weak pump last Friday, only acted up occasionally. Very similar symptoms as the OP.

 

Check fuel pressure. Even though the filter is new, the pump could be old and weak. Somebody might chime in on what the pressure should be. '97+ is 49psi, don't know if prior years are the same.

 

Not necessarily. I just replaced a fuel pump last Friday in the recently bought 1997 Grand Cherokee I have been preparing for a daily driver for my daughter.

It had similar symptoms to the OPs Jeep.

After replacement, everything good now.

 

Agree with the second being weak power steering pump. Mine does the same thing. It's kind of a groaning noise..lol

 

ive never heard of a fuel pump creating a bog situation only on start up after long periods. possibly a bad return valve. but that would lead to long starts. check the connection by the fuel tank and see if that is dirty and packed with dirt or mud. could be corroded.

 

Yeah I know what you mean exactly. I had another fuel pump with a bad return check valve, it would lead to long starts since their was air purging before it gets fuel. A weak pump can possibly lead to low pressure, causing the injectors to not fully open or supply enough fuel. The pump I installed after the bad check valve one just got replaced due to low pressure from the pump. The pressure reading was erratic, jumping from mostly between 22-26psi sometimes up to normal pressure of 49psi. Mine would sometimes be running what seemed to be perfect, then next thing ya know its about to stall while stopped in traffic and making sputtering popping noises because the engine is starving for fuel.

You do have a point about the connector, they get a lot of punishment. Wouldn't hurt to inspect it at all.