limp mode on long grades on interstate

[Hollyfield]

my 04 MCS goes into limp mode when traveling up a long grade on the interstate. Triggers fault code for misfire in cyclender 4. I have had the coilpack changed, plug wires, plugs. Had the car to two different dealers and two independant garages. Dealerships just tell me it's plug or a wire and then blow me off. The guy at the last shop put a computer on the car and drove up a nearby mountain till the fault occured. According to him, the car never developed a miss but he couldn't find the cause.

I'm thinking maybe a problem with the bypass valve or maybe the coilpack is a cheap aftermarket piece and should be replaced with a hotter unit.

Any thoughts? Any contact information as to who to talk to at MINI. Seems like a safety issue (I keep thinking an 18 wheeler is going to land in my back seat).

[marque]

Hi ya

Uuuuuummmmm it hard to tell with out looking at the car really
If they have changed the coil pack and leads and plugs.
There are a lot of other things it could be :-(.

I would check the bypass valve anyway if the car is down on power or gutless it could be Good place to start but.
But it would not throw up a misfire code unless there were other things wrong with the car.
When was the car last serviced ? Is it a standard MCS
I would get you fuel pressure checked on the fuel rail. you my find the fuel filter needs changing and i would also get the injectors checked and cleaned.
You could put a can of fuel treatment like BG44K in it see if it helps if you have a bad injector but if there bad there bad and normally need clean properly

Hope this helps

[Hollyfield]

Thanks for the input, the car was serviced a couple weeks ago. runs great around town. Will check the fuel pressure and infectors.

[marque]

Quote: Originally Posted by Hollyfield (original)

Thanks for the input, the car was serviced a couple weeks ago. runs great around town. Will check the fuel pressure and infectors.

Hi Ya

i take it the car was like it before it was serviced and nothing done during service has caused the problem
It may be one of those thing where you had few faults all together.

If the Bypass valve was on it last legs it could cause low power at higher load/rpm. the valve causes what they call a yoyo effect at about 3000-3500 ish rpm, but again depends on the car, or it can just causes low power and puts car in to limp mod but not always.
The lack of power would be less noticeable around town but more noticeable when you try to stretch its legs. so would be worth a look at it anyway.
Most of the older BPV don't close properly and there a mod to fix this just a case of setting it up properly.

http://www.mini2.com/forum/first-gen...libration.html

Hope this is of some help