2003 Ford Focus Drive-ability

My Focus has 153,000 miles on it. I don’t have a problem with driving flat land and regular acceleration. However, when I try to merge on the highway or go up a hill the car feels like it wants to stall - jerking and sounds like it’s misfiring. My mileage has been horrible. They checked my plugs and “they are beautiful”. The wires are recently changed also. It has not thrown a code for my repair shop to fix nor does it actually stall. The shop told me if I can get the car engine light to come on they’ll have a better chance at fixing it. I’ve used dry gas thinking I had water in my fuel and recently had the fuel filter changed. It doesn’t seem to be weather related just acceleration!

When was the last transmission service?

This sounds like it could be the fuel pump is getting week or could be something blocking up the pump. I am leaning more to not enough fuel getting to the engine.

I would rule out transmission. It does not have the capability to tell the engine to choke. If it does happen again the next time and if traffic allow, see if you can take your foot off the gas put it in neutral and see if it seems to idle or starts to choke if you give it a little gas while still in neutral. Forgot the engine air filter? or racked coil will cause a problem. Get back and let us know.

My brain is asleep:
I know this problem. It happen to my friend: OMG blocked catalytic converter or partial blockage of your exhaust system. (but every situation maybe different) I found out mine is by taking one of the o2 sensors out and starting it for ONLY a little while because you can burn things like wires ect. But it allowed my 2.3l focus to rev all the way and no more bucking while driving and it ran like a little rally car again! So I will try to unclog the debris that is in the exhaust by debris I mean the insides of my cat that rattled apart after awhil

Have the cat looked at. They dont normally charge to just look at it. Most of the time its free

I’ve owned the car since new 18 years. I’d honestly have to check my repair records as I don’t remember any trans service. I’ll have to look closer at my records. Thanks as I didn’t give the trans a thought. Linda

Its not the transmission. Transmission does not have the capability to say work on flat land but dont work when I punch it.

See if your shop will take a drive with you with their scan tool hooked to your car so they can take data from the engine while the problem is happening. If they don’t have a tool that does this, find a shop that does.


This is a fairly good possibly.


I’ll go with a wild guess and say one of the coils is bad. Just because it’s a Ford. But, I’d think you’d get at least a flashing check engine light. A real time scanner would be able to tell which cylinder is misfiring as you drive, if it is indeed a misfire.

Keep us up to date what is going on?

I still haven’t been able to get it to do it again! I filled my tank as it seemed to happen with a full tank. I took it out on the interstate and up the hill with my pedal almost to the floor! No stumbling at all! I have to talk to the guys at the shop and see if they have the thing to hook up to my car. It would cost $85. to buy one but I’m thinking in the long run it would for itself. If only I could get the engine light on or for it to stall! I’ll be sure to update the post if I can find something. Thanks!

They said the plugs are Beautiful . The most beautiful plugs anyone has ever seen . Grown men cry when they see these plugs .

OK , Flag away. I just could not help myself. Resistance is Futile .


Alas, I still have no answers but it had been running fine - until today! I was driving down the road - a flat road with no hills and it stumbled again. I had just been on the interstate and while getting up to speed it stumbled but unlike in the past I just kept pushing the pedal down and it went back to normal! I’m calling the mechanic tomorrow and ask him if he has checked the fuel pump. My husband reminded me that with my 2000 Ford Focus we had the pump replaced early on due to driveability issues! Duh, I forgot as the car had 12 recalls and a new transmission before I traded it for the 2003 5 door as the previous one was a wagon. If that turns out to be the problem I will post. Otherwise I might start looking for another car. I have to drive 200 miles on July 1st and I don’t want this issue!

Have you ever tried a bottle of fuel injector cleaner in the gas tank?
My suggestion is Chevron /w Techron.
Worth an inexpensive try. I use it once a year.

I’d rather find a shop that had one and knew how to use it and interpret the results. If your current shop can’t, I’d find one that could.

1 Like