Engine dies after shifting into neutral

I started up the XJ thismorning and heard a vacuum leak, it was the MAP sensor tube right at the throttle body so I pkugged it back in, then I went for about a 25 mile drive and a couple of times going down hills I put it in neutral(to save gas of course) and the engine would die, it did this like six times and it's never done it before, even when I was running with the MAP sensor tube not plugged in.

What could my problem be? Last night I had the hood up and I was doing some wiring for my light-bar so if I did end up unplugging something where should I look first?

This is a 90 XJ, Renix 4.0, AX-15 and 190K miles

Thanks in advance

You are not alone. i have tried the tps, ics, map, so my only one left is oxygen, ive been researching this for a week now, no one ever seems to post what they figure out the problem solver to be.

Check EGR valve, too. It has a diaphragm on the back (think that is the correct term) that you can press in while you're idleing. If engine dies when you press it in, then it is bad. It gets gummed up with carbon. There's also a selenoid and vacuum lines associated with the EGR system that can have issues.

SCblack2000zr2, PM'd you.

Greg

my problem was a small crack in the map sensor hard line, after that it didt even come close to doin it again.

mine does the same and i heard the timing chain could be the problem. is that possible? or should i just check the egr or map sensor.

Do the easy things first. Check the hardline from the MAP to the throttlebody. Make sure the plug in the side of the throttle body is plugged correctly. IIRC, you can swap it top for bottom and it still plugs in but nothing goes to the MAP. If that is fine, I would think about the IAC. Did you bump it or unplug it? Either way, unhook the battery, pull the IAC, use some carb cleaner and a tooth brush and clean the plunger (pintle). Do not rotate the pintle while cleaning or force it back and forth. Spray carb cleaner in the housing for the IAC and go at it with some qtips. Make sure that the hole that the pintle goes into is clean and there is no buildup. The little hole in the bottom should also be free and clear.

A normal vacuum leak will cause a high idle, so don't bother looking for that. The MAP and the IAC are the most likely candidates.

mattstevanus said:

mine does the same and i heard the timing chain could be the problem. is that possible? or should i just check the egr or map sensor.

Click to expand...

BASICS--year/engine/etc., you may not even HAVE an EGR valve.

Matt...

87-90 have EGR.

sorry i forgot to put i have a 1988 jeep cherokee 4wd 4.0L
i had a bad egr and replaced it with a newer one but still used a few months ago.
theres a cracking hose attached to the side of the air filter box. i dont know if that could be the problem? everytime i take it off and step on the gas the engine will die