My EGR keeps throwing codes too. It is because it is dirty. I will be cleaning it out soon.

Dude. Bad idea.

So Damemorder, does that mean you recommend Premium?

With less than 91 octane, you'll be pulling timing and getting so much KR, it'll actually cost you more in the long run. You're probably also running 'dirty', and may actually be gumming up your EGR prematurely. At this point, it may be best to completely disassemble the EGR valve. Keep in mind that I've never seen a digital EGR that couldn't be fixed in this manner, but sooner or later we'll find one that can't. Yours might be it, but I'd say the odds are still in your favor.

Just don't run less than 91 octane unless it'* an emergency. And don't count on fuel additives and octane boosters to make up the difference. The 'octane in a can' products boast a full point or two of octane increase. This means 0.1-0.2 octane, not a FULL digit point.

And don't settle for just a cleaning. You want to lube the moving parts as well, even if it stinks for a day. Have you considered cleaning with scotch-brite? You may have pitting on the shafts/bushings.

My 97 kept throwing the egr code at me...installed a gm valve....was ok for awhile///turned out there was a piece of aluminum from the case shorting out the computer....

FYI, the EGR valve used from 94-present is a linear valve. Totally different from the 91-93 Digital valve. Most linear failures require replacement.

So it sound like at this point, most everyone agrees that there is a good chance that I have created my own issue. I will run out the last 1/4 tank that is in there now and put in a fuel system cleaner and a full tank of premium, disassemble the valve and clean it thoroughly and clear the codes. Then I will continue to put 91 or better in it and watch and wait. Thanks for the good advice from everyone. I can’t tell you how annoying the SES light has been for me. Must be that OCD kicking in.

I would not use any fuel system cleaner. If you insist, be sure to put it in a full tank. The quote below is from a GM powertrain engineer from a Cadillac site. He is well respected there and I trust his advice.

"All electric fuel pumps for modern fuel injected cars are in the fuel tank and virtually all of them circulate the fuel directly thru the pump to cool the pump. The fuel circulates directly around the armature windings so any harsh solvent in the fuel will eat the varnish like insulation off the armature windings.

This is not a specific problem to Cadillac or GM fuel pumps. Pumps made by Bosch, Nippondenso, Diesel Kiki, Walbro and others are all susceptible to this problem.

Unless your friends that arrived at the conclusion you state have developed fuel systems for automobiles I would say that they are speaking completely from ignorance.

I HAVE developed fuel systems for automobiles and seen MANY failed fuel pumps, from various suppliers, returned from the field. The vast majority of them are failed due to shorted armature windings causing excessive current draw. The shorted armature windings were damaged from chemical/solvent attack from some substance in the fuel. Since those fuel pumps were tested for many thousands of hours in just about any conceivable fuel known to man the conclusion is that some solvent, not normally found in gasoline, was put in the tank.

I have a spool of armature winding wire from a major fuel pump supplier. Solvents in many gas treatments and injector cleaners, if wiped on the wire, will take the insulating coating off. Been there, done that. It happens.

I related an anecdote earlier about my parts cleaning tank that uses a Bosch PFI fuel pump along with dual/dual filters in series with the solvent line both before and after the pump. The tank uses mineral spirits for cleaning solvent. The pump will run forever as long as all it is circulating is mineral spirits. EVERY time someone uses the tank as a catch basin for carb cleaner it kills the pump. EVERY time. Gumout carb cleaner spray is the WORST.....same with Gumout injector cleaner. Need more proof...???


BTW....same is true for injectors....the fuel circulates directly around the windings in the injector...and strong solvents can damage them the same way.

The reason you don't "hear" of this or recognize it is because people do not realize or relate the use of the solvents to the fuel pump failing. They may use the solvent and then have a fuel pump failure months later that was actually instigated by the solvent. They just do not associate the two incidents as it is not part of their thought process that the injector cleaner could be the root cause of the fuel pump failure.

Good luck with the use of the STP product."

If you wish to read the entire thread click this link
http://caddyinfo.ipbhost.com/index.p...system+cleaner

OK. The verdict is in. Borg/Warner electronic EGR valves bit the big one. Found a high school buddy that has his own shop. Had him check it out and the EGR has an internal leak. Replaced it with an ACDelco and have been good since. Haven't actually checked the gas mileage but it appears better. The rough idle is gone and the performance is back. I sure didn't think that 3 new valves in a row could be bad. Guess that will teach me think.