2005 rx-8
 

My daughter has a 2005 RX-8, has 42K trouble free miles up to today.

I tuned it up about 3 months ago. Plugs, airfilter, fuel filter, replaced the tranny fluid (manual trans) and rear end fluid.

Now she says the car runs fine until she gets into 5th or 6th then the car starts to buck like it's losing power.

Could the clutch need replacing?

I'm trying to do some long distance troubleshooting since she's about 2 hours away.

Thanks!

Have you changed the coils & plug wires? If not, might be a good place to start.

No I haven't. Good idea.

Thanks!

More Questions:
Does it buck on short trips or long trips? Morning or Afternoon? Full Gas tank or near empty?
Is the Check Engine light on?
Have you got the Engine codes read?
After it has been driven for 15-20 hours, have her look under the passenger side door and see if the catalytic converter is glowing red.

Short trips

Afternoon

A little less that 1/2 tank of gas

No check engine light, although she said it did flash briefly once.

No long trips planned as she's afraid of getting stuck.

I'd like to hear about the condition of the cat, but right now I'm thinking the fuel pump is getting hot and cutting out. The flashing check engine light is a misfire. If it only happened once, I wouldn't worry about it. If it is the fuel pump, they are $160-200 plus labor depending on the dealer. It is inside the left fuel tank.

Would the fuel pump cause the problem to happen when the car is in 5th or 6th gear?

Yes, when ever there is a load on the engine it would.

Update
 

My daughter brought the RX-8 to the dealership this morning.... barely made it, it died in the dealership parking lot twice. The service writer said it sounded like the cats were bad :(

Now for the good news :D:

When she bought the RX-8 (new) I told her to get the Ford extended warranty. She opted for the ExtraCARE. The dealership screwed up the paperwork so they upgraded her to the PremiumCARE! So it looks like the repairs will be covered as well as a rental car if necessary.

Thanks for all the help!

Update #2
 

Just talked to the service manager.

He said the engine may be toast, but it's covered until 96k....

Needs 3 out of the 4 coils and one plug wire in addition to the cat.

They are going to replace them and then do a compression test to see if the morots toast.

Best thing..... $100.00 deductible + $76.00 for the plugs wires.....

Ford PremiumCARE will cover 10 days of car rental if they have to replace motor.

Mazda extended the warranty on the engine to 8yrs/100K. However, rental car isn't covered under that.

I know, but it is covered under the PremiumCARE per the service manager.