Motor only has 217,067 miles and I can not figure out how it keeps losing oil, it doesn't drip, doesn't have blow by, spark plugs don't look like they've seen any oil. Back during october I repaired a bad leaking valve cover and did the breather tube mod to prevent oil running out of my filter box. Hasn't dropped a drip of oil since. I can top off the oil and have it back to add within a week. Head swap is just about a year old in March. Also is sat for 5 years without a head before I bought it and reassembled it. Runs strong and really good for its age and what it has been through. Does have bad heat soak issues. Does have that normal oily smell that every 4.0 that I've been around has after it's been driven. It just had an oil change and 216,605 when valve cover gasket was replaced back in October. Please any advice? It's my only fuel efficient vehicle I have. The tow rig is killing me with the price of diesel being 4 dollars a gallon.

 

No spots underneath it or smoke coming out of the exhaust?

 

What heat soak issues?

Oil smell like gasoline?

 

Is the oil dripping from the air filter taken care of?

 

Oil doesn't drip from anywhere, doesn't smoke from the exhaust, oil smells like oil. It's had this heat soak problem where if you start the jeep back up within an half hour after it was running at its operating temp it will miss and sputter like its low on fuel, the fuel pressure regulator has been replaced, as the TPS was replace back when it had a problematic idle problem. The c101 connector has been cleaned and grounds refreshed. It how ever doesn't heat soak in cold weather if started within 15-20 minutes. It does have the horrible factory injectors that have been cleaned really well with new o rings also.

 

I'd swap those injectors for sure.

Programbo here on CF can supply you with the correct ones.

 

It only misses and sputter when it is idling and clears up applying the throttle. I'm curious what brand of spark plugs should I be running? It currently has the e3 diamond fire plugs which I heard horror stories about but it runs so smooth.

 

Ditch those pieces of **** right off the bat. NGKs baby!!

How long since cap, rotor and wires?

 

You say within a week the oil level is down.. how far down? a quart? less? My '93 "vanishes" just under a quart between oil changes(5000 miles). It does it pretty quickly too.. within 1000 miles or so after a change. I found that if I just don't add oil to top it off, no more oil "vanishes". The oil level never drops a mm. lower than that. I always fill it at oil changes, but that top quart (more like a fifth) always goes mia. Try running it w/o adding oil and see if it does like mine does. Mine doesn't drip or leak anything, anywhere, and there's no sign of any oil burnin' goin' on with the plugs etc. Just my $0.02

 

It gets about 500 miles a week and so far it hasn't moved. I travel 100 miles a day Monday - Thursday with most of that drive highway so it's going right along with traffic going 65-75 mph. And between Friday and Sunday just about another 100 miles gets put on it. Cap, rotor, and wires were replaced when I put the good head on it. The e3's were in the glove box still in there boxes so that's what I used and it runs just so good. It runs better then the 89 xj with 195xxx miles did.

 

The plugs will be swapped when the time comes for a complete tune up.

 

Take a q tip and unplug the breather that goes from the rear of the valve cover to the intake manifold. Unplug it at the intake manifold end, now take your q tip and swab the inside of the tube. If its all oilly you may want to do cruisers valve cover mod.

 

I have done the valve cover mod which solved the oily air box. My rear PVC tube needs to be replaced, where can I find a replacement?

 

I got the grommet from orielys for a few bucks then you can just match any rubber tubing that's got the same diameter hole for the main tube. I don't remember if the grommet I got came with the little plastic elbow that connects the tube to the grommet though.

 

Have you done a compression test?