Car sputtering and backfiring like crazy after using lucas fuel injector cleaner and 108 octane. Spent all the gas and refilled and still same issue. 06 mustang M90, vmp 500 kit and 10% OD. Before than car was driving normal no issues. Replace fuel filter same results.
All input is appreciated.

Thanks
Fred

 

Are you sure that the old fuel is out of the system? The fuel line can hold about 10 or more miles worth of the previous fuel.

What was the purpose of the 108 octane? Are you tuned for it?

 

remedy for the lucas fuel injector cleaner and it made matters worse!

 

Are you getting an error code? Was there water in the 108 gas? I'd look at the plugs to see if any are fouled...they should all be the same light brown color. Sometimes when you "clean out" an engine, some grime gets knocked loose and messes something up.

 

No engine light or error code. Pulled one plug looked didn't see anything strange or different.
Ordered new autolites HT0's, waiting to arrive to install. While parked I rev engine and it sounds normal, while under load (while driving) it sputters and backfires ugly.
Checked all vaccums for leaks, checked all coil plugs for tightness, all checked good.
Very worried.
All ideas or info will be appreciated.
Thanks

fred

 

Does anyone know what the fuel pressure should be at. I have a feeling the fuel pump is on its way out. Where exactly should my fuel pump duty cycles and pressure be at?

 

Is it unleaded 108? Anything above 105 gets very hard to find unleaded.

 

108 octane from the can sold in A.Z.
This will be the last time I use any fuel additive.
What a nightmare!

Waiting for delivery of a set of autolite HT0 plugs, hoping it will solve my problem.

 

Fuel pressure? Fuel pressure duty cycle?

 

I just went through the same thing with my 06. Exact same thing....

We tried data logging to catch it, but it started out to intermittent. It did get worse in about a week after that. I pulled all the plugs and they all looked good with the exception of the drivers side #2 that was slightly fouled. Replaced all 8 plugs and decided that since the drivers side requires removing the air intake and the throttle body to get to the plugs. I decided to replace all 4 coil paks on that side also.

The problem went immediately away! I really don't think it was the plugs. I'm betting it was a coil pak going bad (they were the originals on the car) My money would be the #2 cylinder where the plug was slightly fouled.

-ed