hi all,

I picked up a 01 5.4 screw and it was a show truck with a Vortech supercharger. It has 17k miles (not a typo.)

Anyways when I stomp on the gas the sc builds some boost but it's just a hog. I won't kick down and downshift nor accelerate quickly. My only comparison I can describe as if this was a stick shift car and I started from a stop in 3rd gear.

I checked the tranny fluid and it's seems ok with no funny color, smell or metal particles on the dipstick.

Now I've been reading about the plugs maybe being the culprit as well as the COPs, fuel filter, maf. This truck has low mileage but since it's 10 years old could it be the engine not the tranny? I'm hoping it's just something simple versus a tranny rebuild.

I'm not getting any check engine lights and it's not idling rough.


- 5.4 liter 17k miles. vortech sc,jba headers,magnaflow catback. no other engine mods.

- it's set for stock boost and I think from my readings it's 7# on the guage

- it has a FMU

- fuel system is stock in tank pump and vortech boostapump. i'm getting about 35# of pressure at idle according to the aftermarket guage and it does increase when i gas it.

- running 91 octane

Thanks all the for help.

 

My guess is exhaust not flowing or low fuel delivery. All that extra air from the blower and no fuel to burn would make it quite the pig. Maybe a pressure/flow test on the fuel system. That is alot of years and very little fuel being run through it, could be gummed up.

But that is just a guess.

 

yea. for the first 2 years it was driven 15k miles so that's not bad but then 7 years it sat most of the time and had 2000 miles over that period. the owner had told me the in tank fuel pump had made lots of noise and it was replaced.

I drove it on the freeway today and it won't really rev up in or out of overdrive.

My Scanguage II showed that the tps readings changed when I punched the gas so I think that's okay. It was also showing closed loop too so I think that's good.

It sure is annoying.

 

#1 we need more info

#2 how much boost is it pullied for?

#3 what spark plugs are in it?

#4 tune, MAF and larger injectors or FMU?

#5 what fuel pump or boost-a-pump is on the truck?

#6 what octane fuel are you using in it??

that's a start...

 

I'll try to answer the best I can.

#1 5.4 liter 17k miles. vortech sc,jba headers,magnaflow catback. no other engine mods. i checked tranny fluid levels and it seemed a little high so i removed about 5-6 oz by using a pump and hose from the dipstick.

#2 it's set for stock boost and I think from my readings it's 6#

#3 the owner was basically unfamiliar with things so i will guess stock.

#4 it has a FMU

#5 stock in tank pump and vortech boostapump. i'm getting about 35# of pressure at idle according to the aftermarket guage and it does increase when i gas it.

#6 what octane fuel are you using in it?? 91 octane

 

I also have a Scanguage II so if anybody needs me to provide a reading from it, I can do that. It's not throwing any codes.

I'm thinking to go ahead and put in new plugs and COP since they're old even though the mileage is low. What do you all think?

Is cleaning the maf something I should consider? I always thought maf was more for issues with idling.

 

Ok. I just ordered new COPS from ebay that members here recommend and a oem fuel filter.

Should I need to change the plugs so soon? I'm going to pull 1 of the fronts and see the condition but reading these nightmares about replacing them has gotten me worried.

 

It is unlikely to be your COPS but if you are going to spend the time replacing COPs you might as well do the plugs. If you do not have misfires your COPs are probably fine. I had over 140K on mine before the first misfires occurred.

 

i'm just baffled on what it could be. I don't want to mess with cleaning the maf sensor as i've had bad luck doing so. Last time I did that the car ran like crap until I purchased a replacement then it was smooth.

I don't mind replacing things even with low mileage as long as the costs aren't too outrageous.

 

honestly it sounds like the fuel pump (the vortech POS) has failed and OR the FMU is not afjusted right and you are running the truck LEAN...

 

tarajerame, do you have any tips on testing either? I'm guessing to feel if the pump is working by hand.

 

remove it... and see if it makes a difference

 

I found this from a very old post here

when i read the boost pressure its 35 at idle and 45 at boost so i'm thinking you're right either its the fmu or the boost a pump which i've read aren't the best.

 

well i had called vortech and they told me the fuel pressure numbers are right because of the 8:1 fmu.

anyhow i changed out the fuel filter and also cleaned the maf sensor while at it. it made a huge difference. the tranny will kickdown and when i was making a right turn i hit the gas and the spun the rear tires. before i couldn't do that. keep in mind i'm running 24s too.

my thinking if a fuel filter had to be changed out at 17k miles good chances other things need to be done too.

thanks guys for the help

 

Glad you got it. Next purchase........SPEEDING TICKET!!!!!!