I have a 2003 F150 with a 4.6 and a M90 Eaton Supercharger. I just got the supercharger rebuilt and I took it out last night and did a little driving. I noticed when I got into the throttle, it was cutting out pretty bad. It would go from cutting out for a few seconds and then it would open up and run ok. I guess I'm not sure what might be wrong with my truck. Would a bad fuel filter cause this? I was thinking a vacuum leak but I think it would probably run bad at any position in the throttle. How about a dirty mass air sensor, EGR valve problem, air/fuel ratio being a little too lean. I just wanted to get a few opinions from you great people on this board. Again, when I take off it spudders and cuts out and it will eventually quit and the truck will start accelerating quickly. Any ideas or is there too many potential things that might cause this?

Thanks,

bixbystx

 

So is this the only time this has happened??? Did you have more than A 1/4 tank of fuel?? Never get into it unless you have more than a 1/4 tank.. I would check in to fuel delivery Fuel filter, fuel pump

you would run ok with a vacuum leak at low throttle/ idle and would def cutout as the rpm rise because the fuel pressure is not keeping up with the demand

Do you have a fuel Pressure gauge ?? if so Whats it read at idle and under load??

Remember running lean can kill an engine so no WOT till you get this figured out

 

I had a full tank of gas. I had just filled up when I noticed this happen. I will definitely not be running WOT. I don't have money sitting around for a new motor.

 

I think I will start out easy and change the fuel filter. It sounds like it isn't a vacuum leak because it does run stronger as the rpms rise. I didn't completely put it to the floor but I noticed it cut out as I was accelerating and it appeared to stop at around 60 mph or so. Just want to find out what is going on. Would a maf sensor have an effect like this or would it just run crappy all the time.

 

It seems like my truck was running fine until I filled up the other day. I might have just gotten some bad gas. Once it warmed up it didn't run well at all. I think I might get a couple bottles of heet and see if that helps any. I think I will also change the fuel filter. I drove around with my LM1 connected and I didn't see any high air/fuel ratios when I gave it moderate gas. I'm not going to get into my peddle until I find out for sure it isn't air fuel related. I guess my MAF sensor could also be dirty. I hear that can make a truck run poorly also. Any suggestions are greatly appreciated. I think I mentioned this before, but I did have my supercharger rebuilt a couple of months ago. My truck might be getting more air into the engine, therefore more fuel might be required. I loaded my program late last night and raised my fuel ratio by 8% to just be safe. My truck seems to run fine as long as I'm not accelerating at a decent rate and I'm not talking WOT.

Thanks,

bixbystx