I have a 2006 mustang with a roush supercharger. Getting lean stumble right after startup and only when hot. Have thrown a lot of time and money. All we can think is a glitch in the tune that Roush flashed, or vapor lock? Ever have a vapor lock issue?
Thanks

 

Refer to the other thread you posted. I do no think it is possible to get vapor lock on our vehicles.

 

Thank you Simon1 for your reply.
This thread is quite different from the other thread I posted about the diagnosis of the Lean bank P0171 problem I am having with my 06 Roushcharged Mustang GT.

I have also heard that it is impossible to get vapor lock because fuel can not boil while under pressure (like coolant in a radiator), but then on the other hand I have also heard that vaporization can happen in hot heat soaked EFI fuel rails.

On the Roush supercharger kit, the fuel rails are about 1 1/2" from the top of the aluminum manifold. The fuel rails are very hot after engine shut down and the car has been sitting.

I wonder if anyone else might have more information of the probability of vaporization
Thanks

 

The two symptoms are probably related. Generally if you have a lean condition it's tune, metered or unmetered air getting out or in, O2 sensors and possibly a dirty throttle body.

If it was a bad tune or corrupt PCM generally the problems will be much more severe.

 

With injector pressures much higher than carbs low 4-6 lbs., your problem is most likely not vapor lock. Also, ethanol gas will percolate in a Mustang 1st. generation six (I own one), dumping fuel into the air stream...flooding the engine. Chances are you have an air leak.

 

It's not an issue i've heard of, i would ask you give us a call and speak with one of our tech guys.

 

Hi Kyle, thanks for your reply.
I did speak with one of your tech guys. He is the one who suggested the vapor lock.

 

Perhaps you might connect me to someone really sharp on these things. Ive called a couple times. This is an ongoing problem for years. Many parts changed and diagnostics.

Thanks, John

 

It's tough to have someone here help with that in regards to aftermarket parts that may have been added as we generally don't stray far from the core components of our own kits.

 

i had a supercharged setup do the same thing on startup, it turns out my MAF was biased and was reporting incorrect airflow rates to the pcm, replaced the maf and issues were fixed, perhaps you should try swapping out the maf and retesting.