Will inoperative EGR adversely effect fuel economy ?

[hypostang]

Title pretty much asks the question I have ,
My EGR had been causing drive-abilty problems ( surging and bucking part throttle cruise)
I thought that I had it cured a while back by cleaning the valve and passages, but it still acted funny . I disconnected the vacuum line and plugged it and the car runs better but ever since my fuel economy seems to be less than before .
According to my trip computer I can't seem to average more than 15 MPG but when the car was driven regularly by my father and I before he died we would average closer to 21 MPG. .
I know everyone's first response may be that I have a heavier foot , but I assure you that is not the case. I plan on replacing the valve and sensor in the near future but I have a 2000 mile trip coming in December and I really want to get the best mileage I can.

[pantera77]

Technically it will, but it will be such a small difference you'll never notice it. I never noticed any difference on my 87 or old 91 between EGR and no EGR.

[gadget73]

Slightly but it shouldn't be 6 mpg. I'd wager the issue is the regulator not regulating. Shoot some WD40 into each passage, and pull the filter out and spray some down there. If that fixes it, the regulator was the issue. I dont know how long a wd40 fix works, but I got a month out of mine before replacing it with a new one. It was still working fine when I replaced it.

[hypostang]

I did try the WD40 in the regulator back before I unhooked the vacuum line , I will grab a regulator from the junk yard when I go .

[mercurygm88]

hmm... I have recently started having a bucking problem whilst cruising as well. I unhooked the vac line from my egr valve earlier and it went away completely. I also pulled the cap off the solenoid on the passenger fender and pulled out the filter unfortunately it disintegrated in my hand. I cleaned out the area where the filter was and snapped the cover back on. I plan to pull the egr valve tomoro and clean it out. As far as this regulator we are squirting wd-40 into goes are we talking about the solenoid with the filter in it that I had apart or something else?

[sly]

hell... I don't have any of those issues and have never gotten better than 15mpg in normal city driving in my 88. Typically it's more around 13 or 14.

with combined miles, I've gotten 19 and highway only gotten 21.5 once. This is all on E10 gas though. Damn the ethanol!

[mrltd]

if the passages are clogged, it wont make a difference. So many issues with older cars.

The EGR does use the recirculated gasses to burn and use less fuel. That's a really big drop in economy though.

[mercurygm88]

As crazy as it may sound i seem to be getting better mileage with it unhooked.

[sly]

if the egr solenoid is stuck open... that would cause a bunch of running issues as well. unhooking the EGR at that point would make things work better.

[mercurygm88]

I know its not stuck open but also do not know if it works. I just know the bucking stumbling feeling while cruising goes away with it unhooked. Im gonna leave it unhooked for a few days and see what happens. If there are no adverse affects im going to say the hell with it. If i have trouble i guess ill have to replace the solenoid, valve, or position sensor. My guess is that the valve prolly needs cleaned out.

[miamibob]

Sure the EGR is the issue?? Temp sensors or IAC???

[1990LTD]

put an appropriately sized vacuum line on the EGR valve (the port that the green line was originally on) and run the car. When it's idling, suck on the end of the vac hose like a straw and see if your idle changes

[mercurygm88]

Sure the EGR is the issue?? Temp sensors or IAC???

Only happens when egr vacuum line is connected. Also if it were a bad iac why would it be causing trouble while cruising? Wouldnt it only be at idle. This is only happening while cruising at a steady speed.

[miamibob]

Agreed! IAC is an "idle issue" like at a light.

[mercurygm88]

Since all 3 items (egr valve,position sensor,and solenoid) are special order only from all the parts stores near me. Im gonna try cleaning the egr valve and what 1990 ltd said and then go from there.