Driving around town today and noticed my car felt like it was skipping. Put it to the floor and all it did was kick back a gear a hold the RPM's at about 3500 and wouldn't go any further. Runs OK at lower RPM's but has an erratic idle. It shut off at a light and didn't want to start. Once it started back idle was OK but still won't run past about 4000 RPM's. That's even just holding it in
1st and easing down on the accelerator. Put my stock program back in to see if it was my programmer but it still does the same thing. This sound like oxygen sensor or coil pack problem ? Any help would be great.

 

sounds like your fuel pump

 

Crap...this could be a million things. Let's start with the simple and more obvious stuff.

Be sure to check all your vacuum hoses. One hose popped-off can cause problems like your describe.

Fuel pump? Hum....they usually just go south and don't "act-up" but that is worth a thought too. Plugged fuel filters can caue erratic idle and a miss-fire type of condition too.

You might have an ECU problem or coil pack issue too. Have you recently washed your motor? Did you get anything wet?

A coil pack would certainly cause a miss.....but it would not prevent the car from reving past a certain rpm.

 

I have washed the motor off but that was 5 or 6 weeks ago. The problem seems like it comes and goes. When I drive to work in the mornings it seems to run OK. Everything is cooler then. It gets worse when everything is hot, as in normal operating temperature. Its still under warranty so its going to the dealer monday.

 

Well I checked all my vacuum hoses and wire connects, everything looks fine. I unhooked the battery for a couple of minutes then took it for a test drive. Drove around town for about 1/2 hour. No hesitation at any RPM but still has a slightly erratic idle.

 

i have 63K miles or so on my 03GT. I had the stock plugs in and not 4 days ago I had exactly the same problem. A set of Autolite 103's fixed that problem completely. I'd start there.

My idle had started to get kinda lumpy and then every time I'd stab the gas pedal the car would sputter and jerk like it was missing... cuz it was. #4 and #6 plugs were burnt slap-up (slightly worse than just worn out).

 

Mine only has 32000 miles on it. It doesn't do it at all untill the motor has been at normal operating temp. for a while. Up untill then it runs like normal, no skippping no hesitation.