Focus Fanatics Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
I might be imagining all this, but my car runs different all the time. In most of my cars I noticed the weather can make a difference but it's not the case here. This happens from one minute to the next.

Hard to explain but sometimes it feels like it's not accelerating as well as it should. Other times it feels fine. This is completely random.

I have no codes, replaced, fuel filter, air filter, plugs, wires, and coil. Running out of ideas. I also confirmed today that when it is really low on gas, it cuts out while accelerating at wot. Still had about a gallon in it when I filled up. Could a bad fuel pump be the issue?

I replaced all these parts because I am not getting great gas mileage and it doesn't seem to change all that much regardless of how I drive the car. My mileage didn't improve, neither did the performance.

Any ideas? [???:)]
 

·
Premium Member
Joined
·
7,498 Posts
My guess is a bad fuel pump

Sent from my PC36100 using Tapatalk
 

·
Registered
Joined
·
91 Posts
First off there is not alot of info to go off of so I'll share what I know.

Air intake temps make a huge difference in mid range accel with my car. Is the issue truely random or with hot or cold weather?

Secondly, If I only have 1-2 gallons in my tank and go WOT above 5k it will cut out as well. I think it is the fuel moving away from the pickup.

Clean MAF?
 

·
Registered
Joined
·
505 Posts
how should u clean a MAF (carb cleaner)?

could be fuel pressure regulator
 

·
FF Affiliate
Joined
·
31,181 Posts
No fuel psi reg on the Focus

With only 1 gallon of fuel in the tank its no surprise you have a mis fire with your engine when accelerating , that would be about 1/4 of an inch of fuel sitting still and taking off none at the fuel pump

Get a datalog and see whats happeneing

Tom
 

·
Registered
Joined
·
51 Posts
Does having the A/C on or off make a difference, thats one place I notice the biggest difference in this car, also are you running premium fuel?
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #7 ·
Thanks for all the replies. I didn't mention but I did clean the MAF and throttle body also. Temperature makes a difference but I think this is something different as it happens randomly.

I guess the pump not getting enough fuel when low makes sense, I just never experienced it with any other car before.

I use 91 octane (the highest available) and the A/C does make a big difference but that's normal. To put it in perspective, the difference in power I notice is similar to having the A/C on or off. Obviously I have the A/C turned off when I experience this problem.

One thing I thought could be the issue is a bad tune on the car. I've only had it for about 6 months and have no idea if it ever got a tune. After I replaced the coil, wires and plugs, my startup and idle improved a lot but only for a little while. Now, again when I start the car it idles real bad for about 30 seconds then it gets better but even after it warmed up, sitting at lights it doesn't feel smooth like I was hoping it would.
 

·
Hatch Nation #136
Joined
·
2,043 Posts
Pull your plugs and take a good look at them. See if they have fouling or if there is any discoloration on them.

Your fuel pump prefilter might be nasty, too.

Any reason you are running 91 oct? Are you tuned to take advantage of it?
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #9 ·
The plugs have about 1000 or less miles on them but I will check them out. The old platinums I pulled out looked fine. I run 91 because that's premium in my area.
 

·
Hatch Nation #136
Joined
·
2,043 Posts
Unless it is tuned for it, you aren't getting any real benefit from using the higher octane.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #11 ·
Everything I read about the car states that it needs premium fuel so that is what I'm running.
 

·
Registered
Joined
·
51 Posts
uhhh, the svt is required to use 91 octane or above, the 2.0 in the svt has a much higher compression than your regular zetec. It says so on the dash, in both owners manuals, and on the inside of the fuel door, so the svt is stock tuned for 91 octane or above from the factory.
 

·
Hatch Nation #136
Joined
·
2,043 Posts
uhhh, the svt is required to use 91 octane or above, the 2.0 in the svt has a much higher compression than your regular zetec. It says so on the dash, in both owners manuals, and on the inside of the fuel door, so the svt is stock tuned for 91 octane or above from the factory.
You are right. I'm thinking Zetec instead of SVT.
 
1 - 13 of 13 Posts
Top