Does not stay running stalls while driving in town

Welcome to 2CarPros.

It could be a few things. For example, although you hear the pump, it may not be producing enough pressure. Or, there could be an issue with the crankshaft position sensor which would lead to loss of ignition spark.

We need to be sure where the problem is coming from because the crank sensor is behind the timing belt cover and isn't a quick one to replace.

Take a look through these links. The explain what the crank sensor does, symptoms of a bad one, and in general how one is replaced.

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

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Next, if you feel that the sensor isn't the issue based on symptoms, check to see if the fuel pressure is within spec. Here is a link that explains how that is done.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Here are the manufacturer's specs for pressure:

Fuel Pressure
Vacuum hose disconnection .................... 330 - 350 kPa (47 - 50 psi) at Curb Idle
Vacuum hose connection .................... 270 kPa (38 psi) at Curb Idle

If the vehicle doesn't restart right away and you have to wait, check for ignition spark. If there is none, then suspect the sensor is bad.

https://www.2carpros.com/articles/how-to-test-an-ignition-system

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I attached a picture of the crankshaft position sensor so you can see where it is located. Let me know if any of this helps or if you have other questions.

Take care,
Joe

Thank you for your answer, however after checking all of the above except replacing the crankshaft position sensor (since the car starts and runs perfectly for the 3-5 seconds, I couldn't believe it was that sensor since it was getting fire). After the car starts and runs a few times , I get a 340 code thrown. That is the camshaft position sensor and I have replaced it with a new one. I also replaced the connector since the old one came apart. However when replacing the sensor connector with the new one I could not remember exactly which wires went where. The original plug had three wires. two black and one pink, but the replacement had three black.I tried to put them back the way I thought the had been, but I still get the 340 code., no matter how I switch them around. Could you tell me how to test them and tell which wire goes where on the sensor plug. At this time I have the pink one in the middle of the plug, but have no idea whether it's correct or not or whether the black ones are correct either. I've tried to check the wires to determine which of the black one is the ground, but haven't had any luck. One more question. When splicing the new connector wires to the original wires, can you just twist the wires together until you know which is correct and then solder seal them. Will they still make a good enough connection to determine if they are correctly connected to keep from taking them loose every time it throws the code? I know this is a long post, but I am down to my last vehicle to drive and it is a 35 year old S-10 with about 400,000 miles on it and could die at any time. Any help would be deeply appreciated. Thanks, Jay

I attached a picture for you. It shows the plug orientation and what each pin should have. You will need to check the wires to determine which is ground (check for continuity to ground) the power and the last is the signal wire. this guide can help

https://www.2carpros.com/articles/engine-stalls

Let me know if this helps.

Joe

I attached a picture for you. It shows the plug orientation and what each pin should have. You will need to check the wires to determine which is ground (check for continuity to ground) the power and the last is the signal wire.

Let me know if this helps.

Joe

I attached a pic for you. It shows the plug orientation and what each pin should have. You will need to check the wires to determine which is ground (check for continuity to ground) the power and the last is the signal wire.

Let me know if this helps.

Joe

OK, so when I crank my car sometimes it will jump and not run smoothly while idling. I changed my spark plugs already. when I take my car out of park and put it on reverse or drive it will die. not all the time but sometimes. and sometimes when I come to a stop sign and I accelerate it will act like it doesn't have much power. any help would be appreciated.

try cleaning the throttle plate with choke cleaner on both sides and iac hole

is there anyway you could tell me where those 2 things would be located

the throttle plate just follow the air duct from the air cleaner to engine. then disconnect it the iac hole you will see on throttle body.

This first happened when driving at 45 mph...I was pressing gas pedal but car was suddenly not responsive (however, still running - it did not cut off), pressed harder and engine responded, but then it bottomed out again and when that happens it sounds like it is in the wrong gear. Each time I press the pedal harder, it responds and repeats the same behavior above. Check engine light did not come on. I pulled over to a stop, then started driving again and it still did the same thing. My brother thought it might be the throttle position sensor, which he replaced, but that did not work. He then disconnected & reconnected the battery and it ran/drove perfectly fine as if nothing ever happened until the next day. The exact same thing happened as the previous day. The cel still did not come on. He disconnected/reconnected the battery again and it drove fine to the repair shop. They say they cannot troubleshoot until the can get the car to do this again.

thats correct. you cannot fix something that is not broke. the next time it happens, you need to go to a shop right away.
the fact that you re set the computer means there may be an issue with the pcm or trans control module.

Roy

so just disconnect the hose running from the throttle body to the air filter cabin and clean it with carb/choke cleaner?

I have the same problem...but shop found no codes...how do I check pcm or trans control module?

yes if yo are really unsure go to tune up on the site here and I know they show the throttle plate and maybe a short video on how to do it.

The car has been running well, but this morning when I started the car, it started fine and idled normally for maybe 2 seconds before the check engine light came on and the engine stopped. It seems as though the engine computer runs some diagnostics and after finding a problem cuts fuel. Any thoughts?

Edit: Also, I can start the car with some throttle input (say 3000 rpm) and the car will shut down regardless. It doesn't seem to be a battery or idle issue.

If the check engine light was on, there is a trouble code stored in the computer. See if you can rent a scanner to check for codes. The codes will identify where the problem is coming from. Some parts stores will rent the tool.

Let me know what you find.

Joe

The car will stall and most of the time compression start right back up. Sometime it won't compression start and I have to pull over let it set a few minuets and it will start and away I go. After 10 miles or so it will run fine and I will not have any more problems until the car cools down completely. I get no check engine light when this happens.

When the engine doesn't start, you need to check to see if there is both spark to the plugs and proper fuel pressure to the engine. My guess is the fuel pressure will be low, but you have to check to be sure.

Do that and let me know what you find. If you need directions, see our homepage under the DIY section. There are both directions and a video to help you.

I can not find a fuel pressure test port on my Kia Optima, from what I found online it may not have one.

then it would have to be checked at the fuel filter.

The fuel filter if it has one is in the gas tank alone with the fuel pump

If I recall, there is a low pressure side fuel filter (IN TANK) and a high pressure one on the outside. See attached pic and let me know if you can find it.

I have looked all over for one and can not find one, online I found that some 2005 Kia Optima's have one by the gas tank but not all and I could not find one.

That is odd. I work for an independent shop, so I am not 100% up on all the models. Maybe yours is different for some reason. All my literature shows one. Have you asked a dealer about yours?

It will accelerate for a moment and then act like it wants to die I pump the gas vigorously and it will catch again and then accelerate for just a second and then just bog right back down again is it my fuel filter and if so where is it located I cannot seem to find it

The fuel filter is not serviceable. The fuel filter is part of the fuel pump. Test your fuel pressure. Local parts stores typically rent out loaner tools. Also check transmission fluid level in case this is a transmission issue.

I had new plugs and wires put in my 04 kia optima now it wont stay running.

if the vehicle was running fine before they replaced the plugs and leads .. ask them to check they have put them back on in the right order ?? if they are on wrong the car will not run because the firing order is out ???