NEED HELP! Rough IDLe, Long cranks, Backfiring!
 

I need help, i'm new to the forum. I have a 04 GT rx8 6spd manual; its got 56k miles, and recently its been idling rough at stops, taking a bit longer to crank (sounds different too), feels like it's losing power through the 1st 3 gears (feels bogged down) and when i redlined it the other day while sitting idle it was backfiring after the 9k rev.... any ideas on what it could be?? Sorry if this was already posted and asked, i couldnt find one with all the problems that i've had. Thanks for your help.

Sounds like it could be lost compression... Which is NOT a good thing. Take it to the dealership, you should still be under warranty right (till 60K?)

backfires are normal, rough idling is normal the lost power isnt get it checked out and have a compression test run on it. the cranking might be because u have the old battery they have a new better battery that should fix it

Mine backfires off a high rev.
Power lose,,,,, visit a dealer.

Try running some fuel injector cleaner through, they may be clogged up, thus causing the loss of power. I had every one of your symptoms.

^^^^ agreed, that helped when mine was running sluggish, as for the rough idol, its prob your a/c making it idol rough, and mine always backfires. Mine also idols rough when warmed up and hella rough with my ac on recirc. But its not sluggish :)

Rotary's that have back firing problems usually are a result of fouled plugs. Weak compression doesn't mean that a rebuild is necessary. Any low mileage rotary with weak compression is only weak cause of excessive carbon build-up. Some time this week I'm going to be posting a thread on doing a proper BG carbon cleaning of the engine. I can almost guarantee it will fix a very large percentage of these typical Rx8 issues and void a possible future engine replacement.

cant wait.

beers :beer:

my car was idling rough and cranking too long, turned out i needed new coils

I had the same issue except for the after burn. It was a bad coil that wasn't bad enough to throw a CEL. It should be under the emissions warranty.

John