Hey guys,
I have a 1998 Jeep Cherokee with the 4.0 I6 and I've been having a ton of issues with it as of late. Right now it is misfiring badly with the valve tick and I can hear a growl coming from the intake when I Rev it up. Shakes the truck when it idles and has no power. Anywhere to start?

 

Start with a compression test.

 

Have you verified with checking codes that it is for sure cylinder #3? That for sure is job #1.

Here are some possibilities to explore for a single cylinder misfire.....good luck!

1. Spark plug
2. Spark plug wire
3. Distributor cap
4. Fuel injector
5. Pulse going from the computer TO the fuel injector
6. Cylinder compression

 

It does not seem like a single misfire honestly and it's either pinging or ticking I don't hear any bottom end sounds. I'm going to get a compression test kit and a set of plugs wires and a rotor right now. This is a nightmare.

 

Also no longer a single cylider misfire. 4 is out to supposedly from the ecu

 

Ok so no compression on cyl 3 and 4, the compression seems to be going in between them. Removing head as we speak

 

Low compression on two adjacent cylinders is often caused by a blown head gasket.

The 0630 cylinder head on your 98 is pretty hearty, so hope that is all this is. Was the engine ever overheated? That is a common cause of a blown head gasket.

Before you put it all back together though, I'd highly recommend you take your cylinder head into a machine shop and have them perform a thorough testing on your head for cracks and to ensure it is straight. This is not expensive and it is absolutely money WELL SPENT before you reassemble.

The worst value in a repair is one that you have to do twice

Good luck and keep us updated!

 

Yup blown head gasket, the coolING system failed a second time a few weeks ago, the day I got it all put back together it did this, never overheated bit it had been running hot. Where is a good shop in the wisconsin area for these heads?

 

So after a few more hundred dollars of repairs I'm back on the road (broken distributer bad crank and cam sensors etc) she's back on the road and running better than I've ever seen her do other than the cold start lifter chatter. Thank you guys for the advice!

 

Glad we could help. By chance did you use new head bolts the last time around, or, at least clean the old ones and chase the threads?