I have a 1999 jeep wrangler that will start, but not idle unless i am giving it gas. someone suggested a possible problem with an egr valve. where is the egr valve located? and does this make sense?

You could possibly have a bad EGR valve which would affect the vacuum which affects the idle. Check for a vacuum leak first then check the egr valve

Could you be hearing valve knock. Did you check valve clearance?

wrangler? YJ? 4WD"?
what engine, what fueling system. Carb. or EFI?
2.5 L AMC 150 I4 Complete engine specs[show] 4.0 L AMC 242 I6 Complete engine specs[4][show] 4.2 L AMC 258 I6 Complete engine specs some 87s have a carb. does yours, (nobody can fix enigine not kwowing both facts above and what transmission,.


stalls , moving, only. at stop lights or between gears.
but never just parked idling.
if its random , that would be the EGR valve sticking open.
if EFI , bad idle switch.
if Carb bad dash pot. on carb.

Sounds like a vacuum leak.

Give me some more information about this problem. May be i can help.

If your jeep has an EGR valve, try removing it and giving it a good clean with carb cleaner. A bad EGR valve will cause surging while driving.
hope this helps
Matt

fuel filter

EGR Valve TurnDriverSide creativecommons.com jQuery(document).ready(function(){ jQuery('.intro .thumbnail a:first').attr('href','http://i.ehow.com/images/a05/29/ff/locate-ford-egr-valve-800X800.jpg'); }); The EGR, or exhaust gas recirculation valve, takes inert exhaust gasses drawn from the exhaust system and reintroduces them into the combustion chamber through the intake manifold. This process lowers the peak combustion temperature and helps combat the formation of Nitrous Oxide (NOx) in the exhaust.
jQuery('.intro .thumbnail').each(function(i,e){ jQuery(e).find('img').one('error',function(){ jQuery(e).remove(); }); }); Difficulty: Easy Instructions Things You'll Need:

• Needle-nose pliers
• Flat-blade screwdriver
• Phillips Screwdriver

1. Step 1 Separate the intake ducts from the air cleaner assembly by loosening the retaining clamps and pulling the ducts away from the housing.
   
2. Step 2 Disconnect the vacuum line from the air cleaner assembly.
   
3. Step 3 Remove the wing nut that secures the air cleaner housing lid to the base.
   
4. Step 4 Remove both the air cleaner hosing lid and base.
   
5. Step 5 Locate the EGR valve. Look at the front of intake manifold. The EGR valve will be bolted to the intake manifold just in front of the carburetor.
   

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The powdery black substance tells me that your egr valve is not working.And that is operated by the vacum sysem.The pipe has probebly come of the EGR valve.

I had the same prblm with my 1989 Jeep, 6 cyl straight, and it was because of the EGR valve, easy to replace and not too costly. EGR valve is screwed on the motor, driver side, and there is a ±1/2" rubber hose attached. Easy to see if device comes apart, cut by rust.