i'vegot an 95 jimmy with a vortec. It irratically idles as if i has a performance cam.
So far i've replaced the fuel filter, cleaned the IAC twice, and checked for vacuum leaks around the TB with propane to no avail.
After some researching it sounds like it could be a dirty EGR or the CBI (?) spider. (hopeing its neither because taking off the intake would suck in the middle of winter)

CEL is ON. but i dont have a scan tool as of yet to check the code.
Could this be a cam sensor or such? (where abouts is the cam sensor BTW)

thanks,
Marc

 

The EGR valve is located on the front of the intake under the throttle body. It can be removed, cleaned, and reinstalled with a new gasket (with an integrated screen) without removing the intake.

The CPI spider is located inside the intake manifold and would require removal of the upper plenum to get to. If you check the fuel pressure, you can either narrow the problem down to a fuel issue or something else. Fuel pressure with the key ON, engine OFF should be 55-60psi. After turning off the key, the pressure should not drop more than a few psi. If it bleeds down to zero, you have a fuel leak somewhere.

When was the last time that a tune up was done? Plugs, wires, cap & rotor??

 

tune up was done recently, although after more testing, i unplugged the EGR, and it ran the same way (after it re-learned to run with out it ~10secs)

im thinking its dirty.

how do you remove it w/o removing the intake, take off the tensioner??? or slide it out like houdini?

thanks again,
Marc

 

If you need to, remove the tensioner.

 

awesome sounds good, easy enough, i'll pick up a gasket and some carb cleaner and try that out tommorow.

thanks,
Marc

 

So I took apart the EGR valve and found thespringheld wide open bya rather large build up of crap. lol I couldn't believe howdirty it was!I ended up cleaningthe EGR valve out by spraying it down with carb cleaner and filling the holes with carb cleaner and letting it sit for 15 mins.Put it back togetherwith a new gasket andBAM, Started up "no problems".
So afterputting a newfuel filter in, cleaning the EGR valve, it's running better than ever! Im also hopingI get better fuel mileage now too. Iwas only getting 300kms to a tank.Theold fuel filterwascloggedso badI couldn't even barely blow through it!(What should a normal 19954x4 Two door Jimmy/Blazer get to a tank)? Im now hoping to get 400 to 450!

Thanks Kyle forhelping me through this problem!!! Truck runs great.

Marc

 

You know, my old 95 Blazer went through a phase of EGR cleaning. On long trips(like 300 miles or so), it would get all sluggish, and the check engine light would always come on. I'd always make it home, though, even though it was running like ****. After the third or so cleaning, I (dumbass) realized that it always occured on long trips. Something about the long haul, would make the carbon break loose, and block the EGR.
For no reason though, it quit doing this after a couple of years, and never did it again.

 

With carbon buildup, there is no real rhyme or reason to it. It is highly possible that a previous owner had used sub-par fuel, causing more buildup. Since you have had it, you have cleaned out that buildup by using better fuels and/or additives.

Animal, glad to help! Also glad that you got it fixed. As far as mileage goes, no one can say for sure what you are going to get because we don't know how you drive it, where you drive it (hills, stop lights, etc) and the other conditions that would affect the mileage. On average, you should be able to get in the 400 to 500km per tank depending on how nice you are to it.

 

Im getting around 500kms per tank with my 95 4dr, I drive 100km per day to work and back and most of the drive is in the country at about 90km/hr.....I was having problems with my EGR carboning up ...the last time I got it I ran the engine for about 3 seconds with the EGR off...it ran at a real high idle...Hasnt happened again since...(I got that idea from a previous post of Kyle's)