CFBabe asked me to draft this post since I'm the gear head B/F.

This has happened 3 times now ... the last two happened today while I was driving the car. The circumstances were similar all three times; those being:

a) It was hot weather -- 80+ deg F.
b) I had stopped and parked the car for 10 to 15 minutes after I had driven it quite a while, so the engine was fully hot.
c) After getting in the car, starting and driving for about 5 to 10 minutes the engine would idle so rough that I though it was going to die.
d) The engine would hardly respond to any gas pedal ... acted like it was going to fall on it's face. Once it started picking up RPMs, it would surge and hesitate until about 2000 rpms. Seemed to be running way too lean IMO -- usually surging is associated with leanness.
e) Never saw any "Check Engine" light come on.
f) Shutting down the engine and restarting did not seem to help. Thought maybe the computer went into "limp mode" for some reason.

Did a search on the board and only found one other instance of rough idle, but there was nothing said about the engine hesitating and surging off idle.

With extended driving after the car gets into this mode, it seems to slowly come back around, but still somewhat hesitant off idle when first moving off from a stop light for instance.

Anyway, it seems like it's hot weather induced, possibly something getting heat soaked under the hood since it only seems to do this after sitting for 15 to 20 minutes after shutdown. Strange thing is that it takes 5 to 10 minutes AFTER starting it up and driving before it goes in to rough running mode. Seems like if a sensor or if the fuel lines were heat soaked that it would run rough right after a heat soak period.

Anyone here experience this phenomena? I suppose the dealer should scan the computer to see if any trouble-codes were set by the ECU, but wanted to see if the board knew any info at this point.

 

I would let the dealer tell you after they fix it.But sense it runs itself out it's probably a sensor.or some minor repair.Have it fixed at the dealer that's why you have a warrenty and free rental car!

 

My Xfire said it was 98 to 100 degrees yesterday here in Seattle.

I had a 40 minute trip on the freeway and then some short stops followed by the return trip down Aurora mostly stop and go until south of the stadiums. Not one beat missed.

 

I had a similar but not indentical situation, where the car would miss at idle after it had been run for a bit... I had the dealer run diagnostics and came back clean and they sent me home after 3 hours even though they sat in the car and felt the missing at idle and agreed with me...

Turned out to be fouled plug 1 of 12 ... Discovered by my local mechanic with no Star Tech Computer, just a few years of experience..

Weird how the Star Tech Diagnostic computer said the car was fine when it wan't... Or do these service depts. not know this equipment yet ???? Perhaps...

 

HeHe - We have been driving around in 110+ degrees for the last week. Hardly drops to 98 during the night :shock:

Luckily, no problems yet - knock on wood :wink:

 

Hey Derek,do you know if there's a better plug out there than stock?

 

I honestly don't know if they are better than the OEM, I probably just think they're better in my little twisted mind, But I put Irridium plugs in, they are the same spec used by Ferrari for the 360.

I really don't notice any difference, except that my mechanic said they will stand-up better to the higher octane fuel that I run in the car, which probably caused my OEM plugs to foul in the first place.

 

Yes, the dealer will have a chance to diagnose the problem ... hopefully the computer has set a code to lead them to the problem. If no code I could be in the same boat as HDDP with a dealer scratching thier brainless heads :lol:. I don't have much confidence in most dealers, so hopefully it's not some bizarre problem.

That's why I wanted to ask the board if anyone else has seen this to see if it was something common. Doesn't sound like it at this point. :evil:

 

I take her in to the dealer in the morning, pray for me.


:? :evil:

 

Well let's hope my engine problem is solved. THe dealer found 9 codes set for multiple misfires. He said he found a related service bulletin that recommended to flash update the engine computer.

Time will tell...........
But if there is a service bulletin out I am suprised no one else has had this same problem really.

 

Ask him for the TSB # so we can post it here for everyone's information. Thanks.

 

So did they "flash update" your engine computer? That's not good news to anyone who has done a Upsolute/SpeedTuning/etc. performance upgrade!

 

Yes, they did a flash upgrade. I don't know exactly what that means. I will try to get the TSB# on Monday from the dealer.

 

My situation:

I had "Missing at idle" problems beginning about 1100 miles. Took it into the dealer and had it Star Tech'd... The dealer said there were no error codes... But dealer mech. sat in car and felt the "missing" rough idle...

He suggested fouled plugs as I run 98 octane fuel in the car. (which is a stretch in my opinion).

Pulled plugs and noticed one with much more carbon on it (which usually means it's not firing properly)... Replaced plugs with Iridium plugs and a tank of 91 octane fuel and it ran beautifully for two days, then started doing the same thing again...

I'm starting to think there is a hick-up in the ECU or the timing has been retarded so much on the OEM ECU that it is running too rich...

Your info on the TSB would be extremely helpful as my dealer says there is not a TSB for this issue... The TSB # should be listed on your repair order, as your dealer must list this code to be reimbursed for their repairs... Take a look at your receipt...

 

Ask your tech to check for high intake temp and low intake vacuum.I have had a couple egr valves giving similar symptoms.

 

Thanks for the info... Will do...

 

Don't ask me why, but I removed the plastic throttle body grill pictured below (against your suggestion) and just left the wire mesh screen, last night... And low and behold my car has stopped missing at idle, all day today... Now since it has been random missing for the past few weeks, I fugure I'll give it another day or so to see if it is completely gone...

Do you know why this could fix the problem I have been experiencing ???

https://www.crossfireforum.org/forum/album_pic.php?pic_id=1928

 

ecu most likely recorded the issue as a DTC code.... Go to the dealer see if you have any 35-10 intermittent codes.... Misfires are recorded in the ecu and it will even specify which cylinder..... rough idle is not usually an air issue it is a spark issue, coil pack bad or spark plug conductor fouled.

Secondly record the gas you buy w/station location and ron/octane rating.

idle issues areas to look into also... secondary air pump, kombi valve stuck open or closed, throttle body needs aligned (i.e. TBA alignment) all drive by wire cars need this done every 5,000 miles. Spark and coil packs, bad MAF sensor (fouled by contanimant).

Next... clear ecu codes so the long and short term fuel trim is recalculated.

Remember.... OBD II cars can be tempermental the ECU is you friend.

 

Could this also be a vapour lock issue since the car seems to run fine until parked hot ????
On our airplanes we always have that problem on hot days if we plan on flying again the same day, we have to pop open all access panels to the noise maker ;-)

But then again the old Lycomings are stone-age compared to the Xfires....

 

Sunny: Weird, since I removed the plastic grate over the throttle body (intake pipe) my car idles perfectly... The wire mesh screen is in place still... I'm really confused since the dealer said no abnormal codes were recorded to the ECU when it was missing... confused... But that's the story of my life...