98 camaro auto, just bought the car a few months ago. drives fine ran good, except gas mileage was only around 20mpg driving country roads to work, averaging 55 mph.. anyway ...........
I keep getting a dtc of 905 which relates to nothing. Car started running rough and set this codes. Cleared it drove it about 40 ft and came on and blinks the engine light and then is stays on..few minutes later it flashes, so on and so on. soon as I clear it it will come right back. Only code it sets.
Cleaned the throttle body, replaced spark plugs and wires. Car runs rough at idle thru 2000 and seems to smooth out, almost like dropping a cylinder. Did a cylinder balance and it seems #5 doesn't change rpm whatsoever. Then removed injector harness while running and no rpm change so it seems #5 has a problem, but waiting on a fuel pressure gauge before I do anything...
Anyone ever seen this code ? As quick as it sets it I would think it would be listed somewhere
Doesn't set any code but the 905

 

If the SES light is flashing, it means that it is misfiring. Have you pulled the plug to verify it is sparking on that cylinder? Could have a bad coil pack. P0905 according to my scanner manual is a Gate Select Position CKT range/perf. I don't know what that is.

 

In a way I pulled the plug. Used a vacuum hoses ( 3/4" long) between the ign coil towers and spark plugs, then took a test light and ground each one looking for a dead cylinder. Found that #5 was really weak, but still was firing grounding through the test light. going to due a fuel pressure test first then read the injector and move it up front to see if it fixes #5.

Thanks for the tip about the code

 

Are you sure that the code is not P0305? That would explain the #5 missfire. P0905 is not a valid GM code according to any of the referances I checked. Also blinking CELs mean that the problem that you are experiencing can cause engine or emission system damage if ignored. I would look into a problem with Cyl 5 and assume the code is P0305 and not P0905.

Massey

 

P0905 is a drivetrain/transmission code. You need to look up what "Gate Select Position Circuit Range/Performance" is referring to.
It's a more uncommon error code, so got me beyond that point.

 

Forget the fuel pressure test; it sounds like cylinder #5 is dead. You've done plugs and wires but you could have installed a bad plug. It happened to me once. Swapping the #5 injector with another one is a good idea but I have a funny feeling that you'll be pulling a head. Do you know the person you bought the car from? Could be that they knew big trouble was coming.

 

I looked on Alldata before posting and they have nothing about P0905. Heck it isn't even listed in their list of codes for that car. Might have to check a tranny shop or dealer for more info.

 

GM diagnostic codes: http://diablosport.com/index.php?nam...wtopic&p=55038
And here's a handy dandy pdf version: http://www.edgeproducts.com/product_...cle-pdf-40.pdf

 

Thanks 69! Saved the links.