xjmaninmemphis

so I bought a 92 xj 4x4 I6 that had coolant in the oil. finally got around to changing the gasket and everything went smooth. Relatively easy. Now everything is back together and it is idling low. When I first start the car (open loop) it runs and idles fine 900-1000 or so. After a few minutes the idle slowly keeps dropping. Maybe 100 or so every few minutes all the way down to 300-400 and keeps running until it finally stalls. I have new distributor rotor, cap, plug wires, and champion copper plugs gapped .35, and the firing order is correct. If I'm not mistaken I have 35 psi at the fuel rail, and you can hear all the injectors ticking away. Recently did a wet and dry compression test (my first time) left the plugs in and no throttle activity, 95 to 100 in all cylinders, and no jump in compression after oil was inserted. Traced all my vacuum lines, cleaned all the gummed up fittings on the intake as well as elbows on valve cover. Now it is recirculating exhaust gases through the intake like it is supposed to. Replaced the only O2 sensor I have on the exhaust (upstream) with a bosch (bad idea?) the exhaust manifold is cracked (where they all crack, at the weld by the flange) and have a few rust holes in the muffler. Cleaned the IAC and throttle body and even disconnected the brake booster vacuum fitting on the intake and sprayed cleaner in there. Engine starts right up and power is there, and good throttle response, but shifts high around 3500 rpm (not the reason for this post) but long story short I am at my wits end with this one.. I NEED HELP!! Please

xjmaninmemphis

Also when the engine is running and I disconnect a vacuum hose from the intake (not the brake booster) it brings the idle up to around 800-900 (normal I would assume) and no misses. Plug it back in and it bogs down to a much lower rpm. Almost like it is starving for air ya know.

cruiser54

Check the line from the MAP sensor on the firewall to the vacuum source.

Programbo

Where exactly is this vacuum line you unplug going to?

reformedricky

Update us please...