Any help/wisdom appreciated

Elvis' jeep

Member
Joined
Sep 29, 2019
Messages
26
Location
North Carolina
Thank you in advance for all help and sorry of I give too much info - just trying to be thorough.

2004 - 4.0 - 5 speed - new to me - 167K on Jeep - 8K on new engine (why i bought it) Tranny needs rebuilt - front bearing going bad, but rest of jeep rust free and cosmetically OK. Engine over heated and killed first engine- PO replaced - have paperwork and stickers still on block and head

Knew it had a power issue when I bought it. Loss of power at highway speeds. Have to drop a gear even for small hills.

Threw code P0306 - misfire in #6 - after a bit began running rough enough the miss was noticeable.

What I have done/checked.:

Ran Cataclean through - 2x's

Checked temp of cat and pre-cats - none are hotter than surrounding pipes or muffler

New plugs

Replaced coil rail

All injectors sound the same - stethoscope

Since engine had been out/replaced - tomorrow is cleaning all grounds and trying to see if any are missing - may post separate help ? for this - service manual not much help. Need to make sure there are not missing grounds

Sunday is checking injectors with multimeter

No Schrader valve to check fuel pressure???? Is there a way?

Any other suggestions are welcome and thank you,

Not a mechanic, but I keep a 70 chevy 4x4 truck running. The new fangled stuff I am not so good at - still wanting a carb on this thing..... My 2nd 04 and this one I will keep. I need to learn how to work on it myself.

thanks again
 
Sure sounds like oversize tires with stock gears .

People don't realize that installing larger tires is the same as regearing, just the wrong direction.

Jeeps sometimes get sold because owners think the power is lacking..and often it's just killed by the large tires and stock gears that are calculated to give optimum performance with stock tires .
 
Sorry for slow reply. 31. 10 50. Goodyear.
We’re on Jeep when I bought it, but are same size as my last Jeep. Nothing huge or unusual

tires won’t make it miss it throw a code??? Any other places to check?
 
Do you know the gear ratio? I have a very similar configuration with 4.56 gears and 35" tires. I commonly use 4th gear to go up hills. 3rd gear if it is steep. I'm also usually between 4800 and 5200 feet elevation.

I guess it could also depend on what a "small" hill is.