Rough idle EGR valve help

texanjunker87 · #1 05-04-2011, 10:27 AM

My truck has recently started to have a rough idle. it does not happen all the time, but about once a day. My idle RPM is usually about 750. The truck has 148,000 miles, and I bought it about 10,000 miles ago. In the past 6 months I have changed the spark plugs, changed the fuel filter, Cleaned the MAF, replaced spark plugs, replaced the IAC and done a seafoam treatment in the oil, fuel and Vacuum lines. One thing that I think may be the problem is the EGR, however I have no idea where it is on my truck.

If anyone has any tips on what I should check out to fix the problem, let me know

I have a 99 ranger v6 4 liter 4wd

Gunner · #2 05-04-2011, 11:05 PM

Well, basically you're looking for something like this (see attached picture).

A vacuum line connects to the diaphragm (round flat silver part) and you have a line from one of your exhaust manifolds (to the valve) that carries the dead, non-combustible gas (from the valve) to the intake manifold where it occupies space in the combustion chamber (along with the fuel-air mixture) to reduce combustion temps. A vacuum leak from that line may cause rough idle, and too much or too little exhaust gas recirculation may hinder they way the engine performs but don't quote me on that last one...I'm not 100% sure.

Alon · #3 05-05-2011, 12:15 AM

http://www.fordrangerforum.com/4-0-s...look-here.html

Check that tube and let me know how it looks.

texanjunker87 · #4 05-05-2011, 10:30 AM

When I first go the truck I was getting po 171 codes, but I fixed the problem with a new IAC, the old one wasn't working and it didn't have a gasket. I checked the PCV hose though and it looked fine.

texanjunker87 · #5 05-05-2011, 10:33 AM

I cant find the EGR still. I found a hose going from the intake to this thing ( see attached picture). Does this have anything to do with the EGR? If anyone has a picture of where the EGR is on a 99 6 cylinder 4.0 I would really appreciate it.