Jeep Info; 2004 Grand Cherokee Overland, 4.7 H.O. motor, 130xxx miles, my family have owned since new (and thus has been maintained meticulously, which eased my decision to fix the issue). Things I checked/noticed: Compression tested the cylinders: some had readings lower than others, easily over 10% variation. Best Selling Grand Cherokee WJ Parts. Quadratec 1.5" Wheel Spacer Kit for 07-18 Jeep Wrangler JK. $89.99 $98.99. Quadratec 23 Piece Spline Drive Wheel Lug Nut Kit for Jeep CJ & Wrangler. From $34.99 $38.49. More choices available. Quadratec '41 Wheel for 07-24 Jeep Wrangler JL, JK & Gladiator JT. $189.99. My wife drives the WJ every day, and its still being used as a "soccer mom" SUV, along with wheelin'. So, I don't want to sacrifice comfort, visibility, or cargo space as much as possible. Obviously safety is an issue, but the WJ has a great structure that will be taking the blunt of a roll anyways, so the cage is the 2nd line of defense. 2005JGC. 2813 posts · Joined 2010. #5 · Dec 6, 2010. P0155 is an O2 sensor heater fault code but its a 2/1 code (bank 2 upstream) so more than likely not related to your current P0420 code. 4.7's regularly break exhaust studs (the back 2) and you would know by a ticking noise while the vehicle is running. Sometimes worse when its cold, if My research has found the HO engine uses a slightly higher flow rate that the standard 4.7. I found out the regular 4.7 uses 22.5 LB/HR injectors, my Jeep 4.7 HO VIN "J" uses 25.8 LB/HR. I'm spending a pile of cash on my 2004 WJ with an HO engine that puked a valve seat. I want everything on the new engine NEW. Sort by Oldest first. 8561 posts · Joined 2004. #25 · Nov 29, 2021. I've been modifying the WJ 4.7 since it came out in 1999. Exhaust alone is worth nearly 20hp if done correctly. It's a very restrictive stock setup. And there's solid gains with programmers, air intakes (for the standard 4.7) and ported throttle bodies. 1994 Cherokee Sport - 4.0 HO - AW4 - 4WD Rob99 said: The next time you want to tell a story but not get people's opinions, rather than post it on an internet forum, open up Microsoft Word, type your story there, then click on the little X in the top right corner and then hit yourself in the head with a sledge hammer. On the down side, the Grand Cherokee can tend to feel a bit "trucky" around town and the powerful V8 is thirsty at the gas pump. MSRP for the plush Overland edition is just below $38,000. At that I have a 02 jeep grand Cherokee overland with a 4.7 ho I was driving and everthing was fine pulled up to a stop sign went to take off transmission would not pull in any gear forward reverse nothing fluid is full and clean not discolored any ideas what the problem may be or where to start. I never had any issues no warning signs it just quit. 2004 WJ Overland 4.7 HO, Quadradrive, Onyx Green Pearl Coat IRO Rock-Link 3'' front, HD short arms rear, Billstein 5100's 265-70R17 Falken Wildpeak AT3, Spidertrax 1.5'' wheel spacers kxRf.