OK, not a "WannaBe" any more (wish I could change name...) Any way, starting about two months ago my 2008 2.4L automatic LT would not accelerate when cold, happened all of a sudden, one day fine, next and ever since not fine. I put the pedal to the floor and its like the car is hardly going for a few seconds and it all of a sudden "wakes up" and decides it will react and takes off. It does happen when warm but not as bad. No codes, Dealer never heard of this problem. I haven't done anything yet other than repeatedly putting fuel cleaner in gas. It is so bad that I have to make sure cars are VERY far away when pulling out in traffic or I will get hit!

Making this my weekend project...I read where disconnecting battery for a bit to reset was a suggestion, I'll try that. Also will replace plugs, already replaced air filter. Is there anyone else who has had this problem and if so, what was your fix?

Thanks, Dave

 

A couple of thoughts spring to mind.....

A failing MAF sensor

A failing TPS(Throttle Position Sensor)

A failing fuel pump causing momentary fuel starvation

Since your dealer did not find any stored codes, fuel starvation would be my leading candidate.

P.S. Your username can be changed, just PM me with what you'd like it to be.

 

Ya Mike, I'm thinking MAF sensor as well.

 

If you decide to muck about with the MAF, be sure to ABSOLUTELY not touch the element ever with anything other than aerosol propelled MAF cleaner!!!!!!!!!!!!!!

I see that you replaced the air filter. Check the MAF connector, to be sure it went "home" all the way.

Has anyone changed the ATF? If so check the fluid level (it can be done, use the search tool).

 

is this pedal delay? also you shouldnt be booting it when its cold anyway, let it warm up to proper operating temps then see if its still 'slow'

 

also check your air filter AND the hose itself..sometimes they get clogged, a member on here from the past noticed a nest of squirrels or something in there

 

If its very sudden, I'd suspect a bad batch of gas too, along with what others have posted, but the octane booster would have helped that...

 

Could be clogged cat., vac leak, bad injector. If one injector is dripping the computer will try to lean all of the injectors.

 

Thanks for the replies.

Pedal delay is kinda what it's like, but it does go when I give it gas, just not very fast. Put a bicycle motor on a motorcycle, kinda like that.

If it were the cat, I would think it would always be lacking power and get worse as it warms up. When the car is running good it is strong and responsive.

Will check vacuum lines.

Dealer said if it was running lean it "should" throw a code, don't know but I do know my ford throws "lean' codes.

Also, my sun roof deflector bracket broke. Any thoughts as to why it can't be riveted from the top? Dealer said it's not a problem, just put a good sealer over the rivet.

Thanks again, Dave

 

Update...Disconnected battery, cleaned MAF and throttle body, changed plugs, inspected vacuum lines (all good) and put back together. Car was 80% better but only lasted for about a week or so and started doing it again. Disconnected battery and cleaned throttle body again this weekend and car is again 80% better. Still has a slower acceleration at times but nothing like it was. The throttle body had quite a bit of black residue build up. I'll see how long it will last.