97 Aurora backfiring/surging/loss of power

[myauroraisthedevil]

Sets code P0300 random/multiple misfire as primary, also sets 1133, and 1153 I think relating to bank 1 and 2 o2 sensors.

Backfiring is severe at all speeds and power loss is extreme. I have changed plugs/wires and o2 sensors in the last year, plugs and wires were AC, o2 sensors varied from Beck Arnley and Bosch. Changed all iginition coils yesterday and the problem has gotten worse.

It seems like the car has jumped time completely.

Any advice appreciated.

[peeweewasblue]

Well I hope for your case you do not have the same problem I had. The timing chains gear intermediate shaft and bearing wore out. This allowed the timing chain to start to bounce and eventually jump time. Now if this was all it was it would be easy to fix. Unfortunately the intake valves are interferance (exhaust are non interferance) and bend.

Do a pressure check on the cylinders. If one head has no compression and the other is fine you have the exact same thing that happened to mine.

Now for the really bad news. Even if you can do the rebuild yourself, parts for this engine get very expensive very fast. Plus when you go to torque the heads down they will probably strip out. GM recomends timeserts for this fix. I found a better design by a company named fulltorque. Now the inserts are $10 a piece and installation is $10 each. So there goes $400 to that alone. Gasket sets are another $300. So as you can see really expensive really fast.

Good luck