Mustangmaster

I got my spark plugs changed and the fuel filter. At that point I had about 1/4 of a tank of gas in it. The first few miles the car didn't miss any. Then it started doing it again. I said "ok, I'll fill up with 93 octane and see if it will go away". It did for several miles but then started to come back again. Since then I've used up 2 more tanks of gas and it is still missing some. Mainly when accelerating from start at low rpms or climbing a hill with low rpms. I also notice I am smelling gas shortly after starting the car almost every time. Like it's coming through the vents. Before taking the car back to the local shop my questions are:

1) Do you think this is still a fuel problem? Like maybe changing the fuel filter again will hopefully get all the water/trash out of the fuel lines? Or can it be run out over time and clear up?

2) I have the Granatelli CAI and MPG Coil On Plugs and I know everybody here thinks everything they sell is crap and that might be causing my problems. Should I try changing the coil on plugs back to the original set? I have a Brenspeed 91 tune running right now with these add ons.

3) Should I do the above in number 2 plus call Brenspeed and order the FRPP CAI and get them to tune the car for that intake?


I tried putting the wiring harness that came with the CAI back on and returning the car to stock tune but it ran worse than the Brenspeed 91 tune. Which tells me Brenspeed has a good tune. What would you folks try?

ski

Make sure none of the spark plugs are loose.
If they're ok, then try a can of Heet water remover in the gas tank.
If no luck, then reinstall the stock coil packs.

Also, a partially clogged fuel filter should not cause fuel starvation at low rpm's.

Mustangmaster

Thanks ski. Well, I went ahead and talked to the guy at the local shop who worked on my car, changing the plugs and fuel filter. He said it was for sure water in the fuel filter. So, it's most likely some more in the gas tank and/or fuel filter. He recommended that I go to the local parts store (Federated Auto Parts) and buy some fuel cleaner. They sold me Berkebile 2+2 Isopropyl 99% Gasline Anti Freeze. Then is says isopropyl gasline anti freeze removes water from fuel and it's safe on sensors.

Then he said if that doesn't clear it out after putting that in and running a couple of tanks of gas, he'll probably have to change out the fuel filter again, then I should be good.

cfr865

I went thru the same thing as you last spring changed out the fuel filter , plugs, gas, ect. I then put the oem c.o.p.s back on, the car run perfect and has every since. The GMS coils are junk in my opinion. I went thru two sets of them, both failed, first set in about 500 miles second set about 2k miles. If there not the problem now they will be.

antonio1988

change the COPs back to the oem ones

Acerbus 2.0

Similar thing happened to me a few times. Check that your CAI is well secured and not coming loose during WOT acceleration, when the engine pulls to one side and the intake pulls to the other.

My CAI has come loose at times when launching hard from a stop. When I slow back down, the car starts to stutter and idle erratically until I get out, pop the hood and screw the intake back into place.

Mustangmaster

cfr865, thanks for the info. I put the GMS MPG coil on plugs when I had 25,000 miles on the car. I have 60,000 now. That's 35,000 miles on them. I have generally had good luck with the 2 Granatelli products on the car. But, I will say I feel like the Granatelli intake is not the best for tuning. Good if you don't want a tune though. I think I'm going to order the FRPP CAI from Brenspeed and get them to tune the SCT for that intake just because I don't have a good feeling about the Granatelli. Plus, I've read that the FRPP intake uses paper filters, not oiled ones and they should be safer, not getting oil on anything in between the filter and throttle body.

I'm going to play out this fuel additive and ride out 2 tanks and see if it cures the problem before I change the coil on plugs back to stock.

JOHNNY

Sound like a bad coil if your check engine light is on pull the code it will help to pin point what coil it is.

Nuke

I'd try the water remover first and if the problem persists, change back the OE COPS. I probably would have changed the COPS first if it had been me.

Mustangmaster

Johnny, I haven't had the check engine light come on and the guy who changed my plugs and fuel filter said it was for sure water in the filter. I'm going to try to get rid of that water in the gas first.

I wish I knew what gas station I got the water from.

I was talking to the guys in the shop that changed my plugs and asked them what they thought of the Granatelli products and also told them that most here at the Mustang forums say their products are crap. None in there actually used their products but did say "well, they've been around for a long time and still in business so, they must be doing something right".