Rainier is Stalling and has rough idle??

richbrown25

Original poster
Member
Aug 22, 2012
4
Ok so I have a '04 Buick rainier with a I6 4.2L engine. It has about 104k miles and has always had regular maintenance done. I bought the truck with 82K miles and am the second owner. I started recently having issues where when the engine was at idle the engine rpms would drop and the truck would stall. The display would then say "Low Oil Pressure". The check engine light would NOT come on when this happened. Then it would start right back up and drive fine. Now it is happening more frequently, so I started googling this scenario and decided that it might be my oil pressure sending switch, so I replaced that, my fuel filter and gave it some fresh oil....no luck the problem still persists. So I kept digging and found out that maybe I had a dirty throttle body, so I pulled that off and cleaned it and made it shiny again. I didn't disconnect the battery, however I did pull the PCM fuses for about 30 mins after reinstalling the TB before starting the engine. The truck has not stalled however it feels like it wants to and the idle is rough. What should I do next? I think the spark plugs maybe need to be changed with some new AC Delcos. What about CPAS or CPA solenoid? A youtube video showed a faulty air soleniod shut off vavle maybe at fault? Need to get this fixed any ideas.......

Thanks in advance for the help.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Maybe an oil change and new CPAS would help. Did you drive around for a while after the throttle body cleaning so the PCM would learn the clean TB behavior?

I'm very impressed at your search skills so far. :thumbsup:

It's never the oil pressure sending switch. :wink:
 

richbrown25

Original poster
Member
Aug 22, 2012
4
yeah i have driven it around a fair amount lets say about 30 miles.....is that enough. I was going to try new plugs and a CPAS. The oil is only a 1500 miles old you think another change is already needed?
 

richbrown25

Original poster
Member
Aug 22, 2012
4
I change the spark plugs and got a new cam position sensor and now it is purring like a kitten! Will clean the CPAS ASAP but for now the problem seems to be fixed no more stalling or rough idle. I think cleaning the throttle body helped along with the new plugs and CPS.

Thanks to everyone for your replies and advice.:smile:
 

gmcman

Member
Dec 12, 2011
4,614
Glad to hear.

One thing to note, when replacing the air silencer there is a large vacuum hose underneath that has been overlooked in the past. A vacuum leak can replicate your symptoms but sounds like you have it fixed.
 

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