Automotive

[sda56336]

I have a 2005 Kia Optima LX manual transmission with 41600 miles. I bought it used about 2 months ago & just recently had to have the fuel pump replaced. Also had some recent tune-up service where the coolant was flushed, power steering flush, brake fluid flush, oil change, fuel system was flushed with some mild carbon clean out of injectors...so it should be running well, BUT I have noticed some "skipping" and some "hesitation" while driving and if I shift from a higher gear like 4th to 3rd as the speed of travel decreses. In the past few days it has happened at least once a day where i'll be driving and the car kind of stalls, the check engine light comes on, but then the vehicle continues to go. I thought it was more evident on hesitating while the AC was on but this morning it shut off again while driving and the AC was not on. It has had an oil sensor of some sort replaced in the past, but it is acting up like how it was before i got the fuel pump replaced. There is also some hesitation when starting, like it takes a few seconds while the key is turned before the engine actually turns over... 

any help so I don't blow another 900 bucks at the repair place??

[AAAPete]

I hate to say it but the excessive crank sounds like a bad fuel pump. It sounds like you are losing line pressure which could be a bad check valve in the pump. It could also cause the intermittent stalling but there could be another dozen things that could cause that as well such as idle air control issues. The best way to know for sure is to have a qualified technician formally inspect and diagnose your concern.

[sda56336]

ust had the fuel pump replaced 2 weeks ago

would an idle sir control issue be a sensor of some sort? I have taken it to qualified technicians but i guess since it doesn't act up at the shop or doesnt have any "active" check engine or warning lights it can't be pointed to a specific problem?? any suggestions?

[AAAPete · Accepted solution]

Because there are so many variables I would hate to see you just start replacing parts without confirmation of defect. The idle air control is usually part of the throttle body. It may be worth leaving the car with the shop for a while (a day or so) so they have the opportunity to recreate your concern.