I am a new Jeep owner , 2000 cherokee sport 4.0 with 141,000 miles. About a month ago the engine light comes on and it's a code for "misfire cylinder 3 ". I replace the plugs which were all very worn and do a reset. That worked for about two weeks and the engine light comes back on with the same code.A few days ago I hear this knocking noise and when I give it gas the noise gets louder.

A mechanic told me it was rod knock as a result of a bad bearing and he could fix for $600. Another mechanic says don't fix it because it's putting a band-aid on the problem. His solution replace the engine and he could do that for $1000. Another mechanic said to first replace the ignition coil and an oil change because that could be the reason for knock. If that does not work than too only replace the lower mount of the engine and not the entire thing. I am so confused and just need to know the best way to handle this issue so that I can get back on the road. Thanks in advance.

 

My advice is to check your litters if you run your jeep with a messed up lifter it could bend the rod and mess the whole engine up.it is definitely not a cheap fix to fix a bent rod but litters can be a DIY job and costs ab. $100

 

None of the mechanics mentioned lifters, but I did see a youtube video that mentioned lifters. To my knowledge the rod is not damaged because the noise just started on Wednesday and I immediately parked the Jeep. I'm thinking maybe I should pay the $90 to PEP boys and find out exactly what I'm dealing with. I bought this because everyone said how reliable a Jeep can be and being disabled, going to see at least 4 doctors and test every week I need dependable.


I'm still not sure what to do????? Do I replace the ignition coil ( I was told this would cause knock also)and have the lifters checked? I don't have a lot of money as I'm on a fixed income,but I have family that will help. I just don't want to be ripped off and taken advantage of.

 

A 2000 doesn't have a separate ignition coil. It has a coil pack / coil rail ignition. That isn't going to give you a knock. So you should rule out the mechanic that pointed you in that direction as he obviously doesn't know his way around an XJ.

What exactly is your oil pressure at idle with a hot engine? Are you ever having to add anti-freeze to your coolant reservoir?

The reason I'm asking these questions is that some 00-01 engines can have the cylinder head crack between cylinders 3-4 because of a casting defect. That can result in low oil pressure, having to add coolant, and sometimes a knock in your engine. Not saying that is what is going on with your engine; just asking questions to try to help you isolate this a bit more.......

 

The best thing you could do is to get some healthy family members to help you replace the lifters. (first have it diagnosed) but if you do this at home and you know what you are doing you can get the job done. My brother used to have a Toyota Tacoma and I helped him work on it,it had a engine knock we fixed the lifters and the knock was gone and the car worked.

 

The oil pressure is over 40 when hot and I did add some coolant a few weeks ago, but I've only had the jeep since November. I'm going to check the coolant shortly. I know about the coil pack and I've priced a new one. Will Lucas help so that I can at least get it to the pep boys or should I get a tow?

 

It sure would be awesome to find a Jeep owner/repair person in my city and state. I sure could use the help.

 

My jeep had a knock similar to what you are describing. Is there any way you could post something like a sound clip of the knocking?

 

Your profile doesn't state where your at. Plus, do not go to "Pep Boys" for anything. Find other XJ owners and partner up or at least find out where they go.

 

I would tend to agree with that. I'd recommend you find an independent shop. Ask around for recommendations if you are unsure of where to find one.

 

This is a link to the sound I am having

 

Hard to tell on the video,..almost sounds like a vaccum leak (like a pump) or an exhaust gasket I assume those are ruled out. Are we leaking (fluids) anything at anytime?

 

This video is not my Jeep, it's one I found on YOutube that sounds like mine. I'll be able to actually post what my vehicle sounds like when my daughter gets home fro church. No fluids are leaking. There is no hesitancy in starting.Nothing has been really ruled out because the mechanic just listened to it ,checked the oil and said replace bearing, another one said replacing bearing is a band aid fix;replace engine. Right now the engine light is on because the coil pack needs to be changed. I've been recovering form surgery and was going to get the work done this week.

The lady I brought this from has maintained this vehicle very well and the shop that had been servicing the vehicle verified all the service. She was always on top of oil changes, the only thing that I did when I got it was change the spark plugs because the engine light came on with a misfire code. The plugs were rough looking.

 

You say you've owned it since Nov. Did you find any receipt for any repairs, namely a cylinder head replacement. As prolonged exposure to coolant can lead to worn bearings, therefore a knock. http://www.jeepsunlimited.com/forums...d.php?t=391831 Regardless, probably a good idea to read this anyways.

 

This may be a long shot but have you removed the spark plugs and checked for bits of anything on top of the pistons? I would think you would have heard a noise before if a bad plug had a piece left over, so I realize it's a long shot.