I have a 1997 Cadillac Concours with 126000 miles on it. I haven't scanned for codes because I cracked the MAF tube and know that that will pop a code. I'm getting a replacement sent out and will swap that in and give it a scan.
MY ISSUE: The car runs at a high idle (1750-2200) in park, runs up to 2500 in neutral and does not drop below 1250 in drive or reverse. This is causing REALLY hard shifting and makes me nervous to take my lead foot off the brake at stops. I replaced the Idle control valve, checked that the MAF was intact and Cleaned the throttle body. This issue still persists.
MY QUESTION: In your experience do you think this would be caused by a bad Pressure release valve (PCV)? OR do I need to get my PCM flashed?
You can't really diagnosis it before replacing that maf housing tube.
This is true. I'll repost when I have that replaced.
As an experiment, you might try to exhaust tape the MAF tube and see if that starts dropping the idle. It probably won't fully seal because those rubber tubes usually have a bunch of reinforcing ridges, but it's worth a try.
What is the condition of the other vacuum hoses? You probably have more than one vacuum leak if those are all the original hoses. They've been under that hood for 25 years.
The part of the tube I cracked was on the joint to the metal portion of the throttle body. I over torqued a screw and cracked the hard plastic on the engine side of the MAF sensor. I'm gonna take it all apart again and replace the MAF sensor, plastic tube that came with a new gasket, the little paper spacer that goes in between the two metal portions of the throttle body, give it another wipe down and swap out my PCV Valve. Then I'll scan for codes after a PCM reset. If none of that works to bring down the idle I'll be taking it to the dealership to get diagnosed. I did get it checked for vacuum leaks and none turned up. The air intake hose is in good shape as well. Everything else runs well on the vehicle, it's pretty clean considering the year. The only other issue is that the "Refrigerant level very low" light comes on constantly. I'll be refilling that through the low pressure valve when I fond some time, I already have the refrigerant and adapter to get the job done.