Hey guys, My 2005 Roadster is stalling at lights. It seems that it occurs more often when I am caught by a light and come to a abrupt stop.. when i try to go again the car hesitates and I have to give it extra gas to go. No engine lights come on the dash when it is doing this. There was one point that I thought the car was going to shut off because it was puttering so I put it in neutral which seemed to bring the rpms back up and then put it back into drive and it ran like normal. I am thinking that I need to replace the fuel filter (as far as I know this hasn't been done and the car has 93,000 miles)
I just wanted to check in with all of you to see if anyone has any other suggestions.
Just a little more info:

I recently changed out all ignition cables (due to me breaking one while replacing the sealent on the engine oil breather)

Thanks for any of your thoughts!

 

Just to clarify things, stalling means to quit to shut off to stop running is that what your car is doing or does it idle extremely low like below 600 RPMs and stumbles? Have you change the air filters recently if so then maybe you didn't get the engine cover securely seated on the throttle body top, have you done a throttle reset lately? Have you checked the PVC hoses to make sure they are still attached or don't have any holes in them? And yes you should change the fuel filter, but generally a clogged fuel filter will cause the car to fall on its ***- sett when you accelerate, check the simple things first, might be a good idea to add a bottle of Chevron Techron fuel cleaner to the fuel tank and see if that helps it. Also a question about the transmission how do you know the transmission fluid was low? The reason I ask is because there is a specific way it has to be checked , as you probably know our cars do not have a dipstick and requires a specific type of dipstick that uses a scale marked in millimeters. the proper fluid level is dependent upon the transmission fluid temperature, the nag1 transmission is very sensitive to proper fluid level in order to maintain good shift quality, that being said, I don't believe the transmission has anything to do with the idle quality, I'm sure other members will chime in and have some excellent suggestions, good luck keep in touch.


Dave.

 

My guess is that a cable is not firmly attached to a plug or two, three?
I always question why people change the CPS it does not wear as there are no moving parts, I think bad connections are the main culprit for problems.
The transmission cap is just missing the lock on it, otherwise it functions the same.

 

Thanks guys! I've gone ahead and ordered air filters and the fuel filter. Thanks for the tips on checking vacuum hoses. I will be sure to do so. I know that when I replaced the seal on the oil breather cover I accidently left a vacuum hose off that comes from the breather cover and it caused the car to shudder just as it does when this issue occurs.

kingdavid54: To answer your question.. no it does not shut off.. it just idles really low and threatens to shut off. The car has always had a low idle but it drops really low around 300 and does this shudder.

onehundred80: To answer your question.. i had to change my cps because my car just wouldn't start in a parking lot one day.. then it shut off at a light or two...and wouldn't start at home one morning.... So I came here on the forum and found it to be a common issue. I just went ahead and replaced it and I haven't had any more issues with it not starting or shutting off. I figured the sensor did its job for 11 years so I can't be mad at it

 

Don't buy your air filters from AutoZone they only sell them separately and you know you need two, Advance Auto Parts has what you need and they come with two in the Box for the same price as AutoZone gets for one. If I remember right they are Purolator filters but when you take them out of the box they say made in Germany.

 

A really cool way to determine if a vacum leak exists: Pull the oil filler cap off. If the engine idle speed varies, the case is sealed well and you have no leak. If the engine idle speed is not effected, you have a vacum leak!

 

Smart idea another way to find them is to use a short burst of starting fluid , but you need to leave the air cleaner on and the engine idling, if the rpm goes up then you have found your leak, if it has no reaction then you do not have a vacuum leak. Be very careful because ether is highly flammable, as long as you don't use it around a spark or open flame you'll be okay.

 

I am having the same issue with almost stalling when stopping at a light and with acceleration.
Thanks for the suggestion on how to check for a vacuum leak.

 

Another trick I've seen the old timers use is an unlit propane torch.
Pass it around were ever you suspect a leak, if the idle smooths out, or speeds up, you found it.
CAUTION !! This can also cure the problem by turning your car into a flaming torch, so you didn't hear this from me !

 

Hey nonamejane, Did you fix your problem with your car? if so what did you find that fixed the problem? Mine has done this a couple of times recently and I'm looking for a cure before it becomes a real issue!

 

I just have to ask; you mentioned "ignition cables", what about spark plugs?

 

Well said, common sense troubleshooting is a long lost art that youtube videos are (after the fact) made of. Keep away from moving parts and spark sources whenever doing this kind of troubleshooting!