Jan Olsson Posted May 8, 2009 Report Share Posted May 8, 2009 I have a high idle problem. EGR and throttle body are clean, no codes, no sticking/binding cables. I have tried a new IAC-valve and a new MAP. Reasons for this is that when I was playing around with the parts in that area, the idle quality and rpms improved. Now my guess is that there are a problem with the cables/connections. It seems strange though, is there a possibility that the systems relearns/clears itself after pulling a connection? Link to comment Share on other sites More sharing options...
Cadillac Jim Posted May 8, 2009 Report Share Posted May 8, 2009 I would check the PCV valve for sticking first. The next thing to check is all of the vacuum hoses for cracks or cuts, or for loose fit on their connectors. After that, look for leaks at the intake manifold gasket and throttle body gasket. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
corkyd Posted May 8, 2009 Report Share Posted May 8, 2009 I have a high idle problem. EGR and throttle body are clean, no codes, no sticking/binding cables. I have tried a new IAC-valve and a new MAP. Reasons for this is that when I was playing around with the parts in that area, the idle quality and rpms improved. Now my guess is that there are a problem with the cables/connections. It seems strange though, is there a possibility that the systems relearns/clears itself after pulling a connection? I had similar problem on a 1992 Deville.. throttle position sensor and another throttle related problem.. fixed it with new parts.. the TPS gets worn from constant use in the same 'range' and has to be replaced. also, O2 sensors can be a problem. I got no codes on the TPS-- the o2 generated a code. Link to comment Share on other sites More sharing options...
Jan Olsson Posted May 8, 2009 Author Report Share Posted May 8, 2009 I have a high idle problem. EGR and throttle body are clean, no codes, no sticking/binding cables. I have tried a new IAC-valve and a new MAP. Reasons for this is that when I was playing around with the parts in that area, the idle quality and rpms improved. Now my guess is that there are a problem with the cables/connections. It seems strange though, is there a possibility that the systems relearns/clears itself after pulling a connection? I had similar problem on a 1992 Deville.. throttle position sensor and another throttle related problem.. fixed it with new parts.. the TPS gets worn from constant use in the same 'range' and has to be replaced. also, O2 sensors can be a problem. I got no codes on the TPS-- the o2 generated a code. Sounds reasonable! I have checked for a clogged PCV-system, vacuum leaks etc and everything seems alright. The fact that the idle is just occasionally high makes me think it is an electrical gremlin of some sort. Link to comment Share on other sites More sharing options...
Ranger Posted May 8, 2009 Report Share Posted May 8, 2009 The '02 does not have a PCV "valve". It has a metered orifice. Have you checked the "plenum" (rubber coupler between the TB and the manifold) for a vacuum leak? It's pretty common. Link to comment Share on other sites More sharing options...
Jan Olsson Posted May 9, 2009 Author Report Share Posted May 9, 2009 The '02 does not have a PCV "valve". It has a metered orifice. Have you checked the "plenum" (rubber coupler between the TB and the manifold) for a vacuum leak? It's pretty common. I reminds me of a famous discussion between James Thomas Smith and the guru about blowing up smoke in someones orifice The system is fooled by vacuum leaks but the idle can be just fine for weeks (around 650 rpms) and suddenly rise to 1100-1300 rpms sometimes even 2000 rpms. I did find a vacuum leak but it is fixed (had an idle at about 700 rpms before). It came from a collapsed air duct, (the hole to the intake resonator/silencer) My next step will be to check the resistance for the TPS Link to comment Share on other sites More sharing options...
Jan Olsson Posted May 10, 2009 Author Report Share Posted May 10, 2009 The '02 does not have a PCV "valve". It has a metered orifice. Have you checked the "plenum" (rubber coupler between the TB and the manifold) for a vacuum leak? It's pretty common. I reminds me of a famous discussion between James Thomas Smith and the guru about blowing up smoke in someones orifice The system is fooled by vacuum leaks but the idle can be just fine for weeks (around 650 rpms) and suddenly rise to 1100-1300 rpms sometimes even 2000 rpms. I did find a vacuum leak but it is fixed (had an idle at about 700 rpms before). It came from a collapsed air duct, (the hole to the intake resonator/silencer) My next step will be to check the resistance for the TPS I pulled the connector and plugged it in again. Perfect idle..hmm I'll guess I'll have to wait and see! Link to comment Share on other sites More sharing options...
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