SVT with sudden rough idle, power loss

swansong · 01-14-2013, 09:49 PM

My SVT very suddenly started to run like crap. Here's the situation. Filled up with gas today. Car has been running quite well, got 29 mpg on the tank on a 250 mile trip. On the way home, a few miles from the gas station the car starts to lose power and runs really rough in gear or neutral. Sounds like rocks rolling around when I apply throttle, gargley and deep sounding. I coast to a stop in neutral, with the car stumbling the whole time. Shut it off. Turn back on and it can barely idle, requires throttle to keep from stalling. Runs terrible, sounds dangerous even. Shut it off. Called AAA and had it towed to my local shop. It's sitting at the repair shop for them to diagnose tomorrow. No CEL through any of this.

Hopefully its something simple, I'm suspecting fuel filter or pump... Better not be timing related since that was done 55k miles ago.

More info:
Car has 135k miles.
Fuel filter mileage unknown, could be quite old as the filter, bracket, and nuts are very rusted. (Which is why I haven't gotten to it.) No mention of it being changed by PO, who kept decent notes and was a Ford mechanic.
For past few months car has had a slight stumble at cruising speeds and occasionally threw P0133 and P0172. Changed O2 sensor, reset ECU, car has run much better since with no codes, but still not 100.0%.
Has Toms Tune. No issues with the tune AFAIK.
New Motorcraft copper plugs and CFM wires.
New Alternator.

Basically, I'll see what the shop has to say tomorrow, but I'll back up their thoughts with what the FF community has to say.

Sponsor · Advertisement

Bwhit1 · 01-14-2013, 09:52 PM

It sounds like what happen when my air box piping came off so the maf wasn't reading the right amount or air

***1sloho*** · 01-15-2013, 09:48 AM

moved u to the technical chat forum.

swansong · 01-15-2013, 09:49 AM

Thanks, forgot about General Tech Chat.

***whynotthinkwhynot*** · 01-15-2013, 10:23 AM

Well, I guess that's one good thing about not changing the fuel filter- you'll change it when you change the pump. My pump has 150k miles/8 yrs on it, and the filter has been changed every 25-30k like it should be. I'm curious as to when it will go out.

As a guess, yes, it is fuel pump/filter time. The engine running conditions you described are similar to fuel starvation. You might expect a CEL, but it probably didn't run with the condition long enough to pop up a CEL.

swansong · 01-15-2013, 10:30 AM

^^ My thinking as well.

Another thing to add: Car sat overnight on the shop's lot. I tried to start it this morning but it wouldn't. Seemed like it wasn't getting fuel.

Quote:

Originally Posted by Bwhit1

It sounds like what happen when my air box piping came off so the maf wasn't reading the right amount or air

I was hoping for this (free fix!) but intake piping was nice and tight. Couldn't find any other red flags under the hood either.

***whynotthinkwhynot*** · 01-15-2013, 10:59 AM

In the future, listen for the fuel pump to buzz. On a Ford, if it doesn't buzz, that doesn't mean that the fuel pump is out- there is still the fuel cutoff, and the fuel pump module. About 90% of the time when it doesn't buzz when you turn the key to ON, that is the fuel pump.

Change that fuel filter every 25-30k miles, and if rust and abuse is a problem up there in WI, then use nickel anti-seize under the bracket, and on the threads of the bolt that holds the bracket down. It's messy, but it works. I buy this stuff by the bottle. It's a lot cheaper than purchasing those $1 tubes. It separates due to temp changes and non-use, but just stir it with a screwdriver- no harm done.

swansong · 01-15-2013, 11:22 AM

Quote:

Originally Posted by whynotthinkwhynot

In the future, listen for the fuel pump to buzz. On a Ford, if it doesn't buzz, that doesn't mean that the fuel pump is out- there is still the fuel cutoff, and the fuel pump module. About 90% of the time when it doesn't buzz when you turn the key to ON, that is the fuel pump.

Change that fuel filter every 25-30k miles, and if rust and abuse is a problem up there in WI, then use nickel anti-seize under the bracket, and on the threads of the bolt that holds the bracket down. It's messy, but it works. I buy this stuff by the bottle. It's a lot cheaper than purchasing those $1 tubes. It separates due to temp changes and non-use, but just stir it with a screwdriver- no harm done.

Can't recall if I heard the pump this morning, usually I listen for it to run before turning the key from Run to Start.

"if rust is a problem up there in WI"... You southerners, so funny.