EGR Valve Help PLZ!!

I have the 95 Jimmy 4.3 and have been having this same problem for a while now. First it starts running a little rough then the SES light will come on I took it to AZone and I don't remeber thr exact code but it was EGR related. I took the EGR valve off, cleaned it with Brake parts cleaner, put the screened gasket on and the thing runs fine for a few days, then it seems I have to do this same routine once a week.
It really doesn't look clogged or stuck when I take it off. But it seems to fix it for a week or so. I've let it go a little longer this time to see what happens and now my SES light is flashing and it runs horrible. I drove it around the neighborhood to see if it needs to be blown out, when I give it gas it gets worse, but when I let off the gas it smooths out some.
Any advice would be appreciated.

Z or W engine and PCM or VCM computer>
Electronic or vacuum EGR valve.

We need the code no.
If check engine light is flashing like blinking you have a missfire.

Get the codes read and cleared and see what mes back and post back code no.

Can you feel a engine miss?
Does it idle good?
What is the engine vacuum reading at idle and at 2K RPM?

The engine code is W.
The EGR valve is electronic.
And I hope this doesn't sound stupid but I'm not sure how to tell which computer it is??

I'm not sure if I can get it back to the parts store it's so bad now.
I'll try to clean the egr valve again to see if I can get it that far. The parts store is about 4 miles away but through alot of traffic. I may just need to buy a scanner. I'll probably need it later anyway.

No it did idle ok, but not now. Now it's really rough. The rpm jumps around 1k-2k.

VCM is on the fender under water tank.

What is the vacuum readings.
Get the code no.
Check egr valve for carbon ball under pintel. Like Stuck open.

Well I made it to the parts store and back. (Barely) Anyway I have new codes now and none are EGR.

P0700 ?
P0300
P1100

I know P0300 is multiple misfire but I'm not sure about the others.
I usually get a print out on it, but not this time, I guess the printer was broke.

Anyway, from these codes now what should I do??

Also would the P0700 transmission code cause the misfire code? And by the way now the ses light isn't flashing. It does that intermitent.

Well I made it to the parts store and back. (Barely) Anyway I have new codes now and none are EGR.

P0700 ?
P0300
P1100

I know P0300 is multiple misfire but I'm not sure about the others.
I usually get a print out on it, but not this time, I guess the printer was broke.

Anyway, from these codes now what should I do??


300 only says misfire.

code 1100 is a intermitent map sensor problem.
Work on and repair it first.

Clear codes and see what comes back first.

misfire may be connected to transmission cod.
map sensor may be part of misfire code problem.

Its been really cold here and I haven't been able to work on the jimmy, but I was wondering what would cause the intermitent map sensor, wiring or does it mean it's probably going bad? Do you know if the MAP sensor can be tested.?

Can be caused by bad wiring or bad vacuum or bad map sensor.
Twist and wiggle wiring.
Check for good vacuum to it.
Get a voltage reading on map sensor when code sets.

Ok, I'm back It was a little warmer today. So, I replaced the map sensor and plug, played with wiring, No difference.
I decided to get a water bottle out and spray around the vacumes, and etc.I found a plug wire completely disconnected from the distributor cap. I have no idea how that happened??? But I reconnected it and it made little difference in how it runs. Could something have caused it to jump off. I do hear a little clicking around the coil and distributor, but I can't pin-point it. I've studied under the hood tonight to see if anything is arching, but no blue spark coming from anywhere.
With each of the things I've done today I reset the computer, but the check engine light comes on as soon as it starts. I let it run a few minutes to see if it straigtens out and then the check engine light starts flashing again, so that tells me there is still a misfire. Is there a way I can check the coil to see if it's putting out proper spark or what else would you do??? This thing is causing me to go gray!!!

Also I forgot to ask, but can I check the vacume to the map sensor with it unhooked, because the map sensor mounts in the vacume on the intake. I did not try that, but I did clean the port out before I put it back on.

Varying or low fuel pressure can cause the Manifold Absolute Pressure err codes, check your fuel pressure hot and cold. Start with the basics.

On that set up just check the engine vacuum on intake.
Brake booster hse is a good place to check engine vacuum.

Ok, I'm back It was a little warmer today. So, I replaced the map sensor and plug, played with wiring, No difference.
I decided to get a water bottle out and spray around the vacumes, and etc.I found a plug wire completely disconnected from the distributor cap. I have no idea how that happened??? But I reconnected it and it made little difference in how it runs. Could something have caused it to jump off. I do hear a little clicking around the coil and distributor, but I can't pin-point it. I've studied under the hood tonight to see if anything is arching, but no blue spark coming from anywhere.
With each of the things I've done today I reset the computer, but the check engine light comes on as soon as it starts. I let it run a few minutes to see if it straigtens out and then the check engine light starts flashing again, so that tells me there is still a misfire. Is there a way I can check the coil to see if it's putting out proper spark or what else would you do??? This thing is causing me to go gray!!!

If the clicking noise is spark jumping look cap and wires and rotor over good.
Also a bad plug can cause spark jump,
To check for good hot blue spark get a spark jump spark tester.

Ok i'm getting somewhere!! I started taking the wires off one by one to check for the clicking sound and I found that the coil wire was slightly loose on the cap end and was VERY corroded, so I bought a new cap and coil wire, so now I have no check engine light, I guess that explained the misfire codes and other. It's still barely running, but it is a little better.

While under the hood I realized that I have another noise I can't find and hopefully it leads me to my main problem, but when I push under the hood acceleration I hear something kicking on when I give it the gas and it goes away when I let off. But its very loud, I noticed it last week, but I thought it was a plane flying over and didn't pay any attention until today. No wheels turning, mind you I'm under the hood. But seriosly it sound like an airplane flying over. I read some of the other threads for airplane sounds, and mine is not the rear end or wheel bearings, because it's sitting still. It's automatic, so I wouldn't think the fan clutch. I have the heat turned off. But it does seem to be more on the drivers side.??? I was sort of hoping the ses light would come on so I could at least no where to start. It's almost like a large fan is kicking on when I give it the gas, but the cooling fan runs constantly, so I'm stumped.

Also before any of the proir problems started the truck was very quiet. You would almost think it wasn't running. Not now, and its not a loud exhaust sound. It just sound like an airplane flying over.

Should I start a new post for this problem??

Thank you soooo much MT-2500 for helping me through the codes earlier, I've read ALOT of your posts and you are the man!!!

You are welcome and thanks for posting back how it goes.
On airplane noise the only thing I can think of is the cooling fan.
Does it do it cold and warm and hot?
When the noise gets loud hold your hand over top of engine and see if you can feel a lot of air blowing from rad area.
Also with engine off feel fan clutch for lose or wobble or being tight.
And look for any place it could be rubbing fan shroud.
Good Luck

Fan seems all intack. But I was wondering, does this model have an air/smog pump. One of my friends ask, and I wasn't sure. But the sound also seems to get a little louder when its up to temp. I found a bolt missing on the shroud, and replaced it, but it didn't make a difference.

Look on it and see if it has a air pump.

I'm used to the old style air/smog pumps. Unless this model is shaped totally different, it doesn't.

Could the 4 wheel drive make noise if the vehicle isn't moving?

Well I've let it run about 20 minutes or so and now the ses light is back on, we are under winter weather advisory, so I probably won't be able to get it scanned for a day or so. I'll post back when I get it scanned. Hopefully it will help the airplane noise.

I do no think yours has a air pump.
But always look to be sure.
99-01 have a different air pump.
http://www.automotiveforums.com/vbulletin/showthread.php?t=564664

Get the code and post back code no.
On the fan clutch and noise feel it and see if fan blade is turning free or tight.

They may drag when real cold and make a fan noise.
After warmed up it 185-190 should not be blowing hard or making noise.
But it should kinck in and make a fan noise after around 200 or more.

You can feel air blowing or listen to the fan to see if it is kicking in.
Good Luck