91 EGR Problem? Codes 33 34 and 35

[mholhut]

I recently (a month ago) replaced the VC gaskets. After which, I forgot to completely tighten the EGR vavle where it mounts to the intake plenum. I ran the car, which drove poorly BTW, and quickly discovered my mistake... but not before loosing one of the EGR bolts. So, after removing the other bolt to find a replacement, I reinstalled the EGR valve onto the intake... minus the gasked which disappeared into the bowels of the engine bay. It was replaced a day later. Also during the intake reinstallation, I broke one of the vacuum hose that leads to the back of the plenum. I repaired it that day.

Recently, the car began loosing power. It felt like I was driving uphill, at 5,000 feet, in 99% humidity on a 110 degree day. Secondaries open, but serious lack of power. I also get intermittent CEL's at highway speed... particularly after accellertaing onto the highway. The CEL stays on for a few minutes and then goes out until I put my foot back into it.

Ran the KOEO and KOER tests:

KOEO
52 - Power Steering Pressure Switch/circuit open - PSP (Again, probably didn't turn the steering wheel again.)

Meomory Codes
33 - EGR did not open/ respond during test or if memory code, did not open intermittently - EVP EVR PFE

34 - EGR did not respond properly during test - EVP
EVP sensor is/was high - EVR
PFE sensor is/was out of range - PFE

35 - Engine RPM's too low to test EGR system - EVP
EVP sensor signal is/was high - EVR
PFE sensor signal is/was high - PFE

I then ran the KOER test:

12 - Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too low) - ISC

52 - Power Steering Pressure Switch/circuit open - PSP (Again, probably didn't turn the steering wheel again.)

I haven't checked the nostrils for desbris yet (will be doing so in about an hour.) I do not remember cleaning them when I had the intake out of the car for the VC gasket installation. My guess is that they're pretty balled up since Im getting EGR codes and an IAC code. Just wondering if it might be something else like the EVS or the EVPS?

Thoughts?

 

[BamSHO]

question, didnt know the 91s had EGR on them. So not sure what the deal is there. Ive had 2 92's and a 90 with no EGR. I have a 90 computer here and a non EGR intake if it still acts up. If you want and I can send to you to see if it helps.


Brian Michael
98 silver Gen 3

 

[Phoenix]

question, didnt know the 91s had EGR on them. So not sure what the deal is there. Ive had 2 92's and a 90 with no EGR. I have a 90 computer here and a non EGR intake if it still acts up. If you want and I can send to you to see if it helps.


Brian Michael
98 silver Gen 3

CA models had EGRs. All 3.2 auto had EGR plus all 3.0 and 3.2 from calif had EGR.

 

[FastAndFurious]

question, didnt know the 91s had EGR on them. So not sure what the deal is there. Ive had 2 92's and a 90 with no EGR. I have a 90 computer here and a non EGR intake if it still acts up. If you want and I can send to you to see if it helps.


Brian Michael
98 silver Gen 3

California 91 had EGR. Mine had one too. Stupid EGR tube breaks easily too. I'm just glad my current SHO doesn't have one.

 

[mholhut]

Yeah, it's a CA car.... therfore, the need to deal with the EGR.

 

[BamSHO]

When was the O2 sensors changed. A 93 ATX i had boughten had some what the same problems. I replaced the DPE sensor and both O2s. If the O2s arent that old, try the DPE. The 98 I got, the hole into the intake from the EGR was completely carboned shut, took 1/2 hour to clean out. It ran like crap too. Sorry about the first post, didnt really think it thru, was getting ready for bed before work.

Brian Michael
98 silver Gen3

 

[mholhut]

I don't think the O2's have ever been changed... she only has 75k on the clock.

I looked at the nostrils and the were open; not clean but open. Same with the van hose port on the rear intake. I reset the codes an I'll take her out for a rip today to see if the CEL reappears.

 

[Shoshone]

I had check light on for EGR, forget the code. Removed the intake runners and cleaned out all EGR passages. And all the runners. Everything was a goopy oily mess. Check light out, EGR working, passed Smognazi CA test.