tannertaylormusic Posted June 22, 2010 Report Share Posted June 22, 2010 Rough idle and hesitation while accelerating started a week ago, has become much worse. Didn't show any codes yesterday, but switched out the fuel filter today and now I have two codes: PCM P1645 PCM P0300 Just had the intake manifold, coil, water pump replaced several months ago. Mechanic said, at that time, that the head gasket was good (I know that can be a prob on Northstar engines).. Anyway, I need help!!! I'm not much of an electrical guy but am able to replace most parts. PS - Also noticed that it's hard to get the engine to get up past 2000 rpm. Massive loss of power for this engine Link to comment Share on other sites More sharing options...
Ranger Posted June 23, 2010 Report Share Posted June 23, 2010 How old are the plugs and wires? I had similar symptoms after the fuel rail recall on my '97. Old wires seem to break down after being jostled around as would have been done in replacing your intake. A new set of A/C Delco wires did it for me. Link to comment Share on other sites More sharing options...
tannertaylormusic Posted June 23, 2010 Author Report Share Posted June 23, 2010 How old are the plugs and wires? I had similar symptoms after the fuel rail recall on my '97. Old wires seem to break down after being jostled around as would have been done in replacing your intake. A new set of A/C Delco wires did it for me. I've only had this particular Cadillac for 7 months. How do I tell if they're bad - I'm guessing they become brittle.. also, what do i have to do to check out the condition of my spark plugs? Link to comment Share on other sites More sharing options...
tannertaylormusic Posted June 23, 2010 Author Report Share Posted June 23, 2010 Thanks for the info.. I'm going to do some investigating tomorrow. Gonna take the spark plugs out and look them over and run a volt meter on the spark plug wires to see if there are any abnormalities. Link to comment Share on other sites More sharing options...
Seanmannino Posted June 23, 2010 Report Share Posted June 23, 2010 Not sure what all has been checked but I just had this issue a couple weeks ago and wasn't around a computer so I took it to a mechanic. Lack of power even when standing on the gas pedal. At first glance he thought it was a plugged CAT but then had his GM certified tech get into it and the found the Fuel pump was only pushing 20 PSI. Replaced that and fixed some wiring harness issues for the O2 Sensors and she runs like a raped ape now. Check your fuel pressure might just be the issue. Sean M. 1997 Cadillac DeVille Link to comment Share on other sites More sharing options...
Cadillac Jim Posted June 23, 2010 Report Share Posted June 23, 2010 P1645 Evaporative Emission (EVAP) Vent Solenoid Control Circuit You have some issues in the wiring harness. Some things are unplugged, loose, or some wires are getting damaged by the exhaust heat or some such. The plug wires are very sensitive to being moved around, expecially after they get really old. Even new wires can cause problems if they are not routed pretty much exactly like the FSM says because the Northstar spark so strong enough to couple spark from one wire to another. Old wires can crack, resulting in arcs to ground; you might be able to hear this under the hood, and even see it at night if you remove the beauty cover. -- 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...
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