Need advice - jerky throttle response at lower speeds

[myat35]

Newbie here. Just bought an 03 OB with the 2.5, 4 cylinder. Here's the issue I'm seeing and need some advice. I'm noticing when stepping on the accelerator at slower speeds (below 35 mph) it jerks 2 or 3 times. It happens when I left off the gas pedal (such as coasting to a light) and then give it gas again. The jerky throttle response only seems to happen at slower speeds & rpms. I tried to recreate the problem on the freeway, but only happens at slower speeds.

I'm also noticing lower MPG than I would have expected.

Any thoughts/suggestions as to the jerky throttle response?
Thanks!

[Boxxerace]

Curious, do you have a manual transmission?

[myat35]

No, it's an automatic.

[Boxxerace]

In general, something like this could be the result of a number of things. It sounds like your not having a computer code called out, but you might have it read at a service shop or dealer just to be sure. Something along the lines of a lockup converter (if there is even one in your AT) being wacky might do it.

The main other suspect is the engine itself. Possibly a situation of bad gas (water in the gas, you can get a product at a parts store to get rid of it). Maybe another situation of a sensor being all wacky.

Does the jerkyness happen with the engine cold and warmed up?
How about in every gear, including reverse?

After rereading your post, I wonder if your seeing a bit of lag in the drivetrain. What I mean is the slack in between the engine and the wheels. On my Subaru, you can rock the wheel back and forth about an inch while in gear (and in the air). That lag can create a situation primarly at low speeds and low RPM that makes a jerky feel kind of like driving a manual transmission truck going between coasting and engine power. I cannot say I have experienced this in an automatic, but it still is a distinict possibility.

[myat35]

Thanks for all the good tips! I have some great places to start looking now. Thanks again!

Rob

[steved]

Something to try:

I have found the throttle plate carbon'd up on my 2.5L...get some throttle body spray and hose the inside of the intake and throttle plate down...it will take care of the touchy throttle at low speeds...make sure you get the backside of the throttle plate...

This cured both my outback's and my GF's mustang's rough starting and jerky throttle response.

steved