John Allbright

I apologize as I'm sure this has been discussed before. I am having trouble with my 99 Cherokee 4.0 i6 4wd automatic. First let me run down what my brother and I have done to it since purchase a year ago. About 8 months ago we put on new injectors (Siemens 4 nozzle), new wires, spark plugs, distributor and button. About a week ago we put in new lifters and rods, new cylinder heads, rings, and oil pump. We have it running...sort of. It starts in an extremely high idle (I have no rpm guage and don't know how to tell manually). We have tried unplugging/plugging back in the Map Sensor and it idles down a little and then starts jumping around, but when we hook it back up the rpms go back up. Checked the TPS and it seems fine. I know next to nothing about this stuff and my brother is fairly competent but doesn't know everything. We just noticed about 20 minutes ago that injector 1 will drip if we shake it and injector 3 is soaking wet. We know to check for vacuum leaks and will do so shortly but I was hoping that someone could give us any ideas on what could be causing it besides a leak or bad TPS. I can't afford to let this thing take a dump on me. Thanks in advance for any advice and for taking a minute to read this.

Edit, after posting we checked the injectors again and they aren't leaking any more after taking them out and reinstalling.

93XJeeper

now sure about the high idle, but a glowing red Cat means that it's bad I'm pretty sure. Lol

Bustedback

Is the intake manifold seated properly against the cylinder head?

BlueRidgeMark

Codes?

Vacuum leak is a prime suspect.

Larry's XJ

Extremely lean from air leak or really plugged cat. No codes?

rzldzl

no pics?

John Allbright

Sorry guys I don't have any pics. My Jeep is at my brothers house where he is working on it and I live an hour away driving a spare car. Yes the intake manifold is on tight. It was late where I live when I posted this and we ran out of daylight (no garage to work in). It's also raining and is supposed to continue through tomorrow. It may be a couple days before I can get any pics or look at it any further. Out of curiosity would it have been possible to cause a bad Catalytic Converter when we replaced the Pistons and other parts I put in over the past few weeks? It sounded and ran fine other than a bad knocking that came on all of the sudden and that's how we found the bad lifters and and busted piston head. I don't have a code reader but plan on getting/renting one as soon as I get a chance.

Waynerd

Glowing hot exhaust= very lean
High idle= vacuum leak
Vacuum leak= lean condition

Waynerd

Likely intake manifold gasket if it's that lean.

s346k

check the spark plugs. it sounds like you're going to melt them. as stated: red exhaust means lean condition or blockage. getting it to run and idle correctly is the first order. I'd be looking everywhere for vacuum leaks first, especially the intake manifold.