Cold Start Hesitation - Fine When Warm

[jonescincy]

I have a 2000 Toyota Corolla and have been having a problem when starting the car first thing in the morning or when leaving work to go home. The car starts fine and seems to idle fine. Once you try to give it some gas initially it boggs down and can sometimes stall. Once you give it a little rev or leave it idle for a while it seems fine and usually works without any problems after that. My wife took it to get it looked at and they told her it needed a tune-up and a new belt. Since it had almost 60,000 miles I thought OK fine, probably needed it anyway. Well that didn't fix the problem. Next they told her the Idle Air Control valve needed to be replaced, that was the diagnostic code they got. Since I didn't want to fork out any more money than necessary I took the car myself to Toyota told them what I was told and had them look at it. They replaced the IAC valve since that is the code they read also. That still didn't fix the problem. So now I'm wondering if there is something different that is causing the IAC error code even though nothing is wrong with the IAC valve.

I'm still searching for the answer as to why it would only hesitate when initially started. This really didn't seem to be a problem during the winter months but I seem to recall it did this a little bit last year for a while and then sort of went away. Now that it has gotten warmer it seems to happen all the time after it has been sitting for several hours. I've seen a lot of posts for replacing fuel filters to fix hesitation problems but would that go away once the car was warmed up? I can replace the fuel filter myself and probably should anyway but if this isn't the problem... Any ideas on things to check would be appreciated. I figure with the new belt and the tune up I should be well over 100k miles before I have to worry about that stuff again. The IAC valve was the problem code the computer spit out so replacing that was logical but now that I've spend a couple hundred dollars on a useless repair I figure it is probably going to turn out to be a $10-$20 part and a few minutes worth of work I can do myself. Any ideas?

[Unity Jon]

it sounds like you have an Air leak and when the car warms up the pipes warm (expand) and close the air leak point, check all your vaccum hoses for splits and / or loose fittings (when cold).

[H Kaul]

I have a 2000 Toyota Corolla and have been having a problem when starting the car first thing in the morning or when leaving work to go home. The car starts fine and seems to idle fine. Once you try to give it some gas initially it boggs down and can sometimes stall. Once you give it a little rev or leave it idle for a while it seems fine and usually works without any problems after that...

I'm having a similar cold start problem with my 2006 Corolla 1.8 AT [51,000 km] for a few months except its not identical:

• the problem only happens in the mornings [temp is around 15-20 C which is not cold on an absolute scale]
  
• it does not stall after that
  
• i replaced my factory Battery 2.5 years old on the advice of my mechanic but that did not help [though the problem did go away for about a week and one of the 'cells' on the old Battery was dead]
  
• i took it to the dealership who could not find any problems [no error codes in the diagnostic]
  

any suggestions?

it takes 3-4 tries to get started in the mornings and the starter checked out fine also

thanks!

[nightrax]

What error code was it out of interest if its the IAC valve it would prob be P0505.

I got the garage to clean out the valve and she works like a treat now, you could also try cleaning the MAF sensor takes about 10 min to do.

Def check all the vacum hoses have a look to see if anything is stuck in the air filter blocking the flow to the engine, it could be the CAT thats gone.

You could also try and reset the ECU using the fuses to see if that helps, it might be a code that has gotten stuck in the ECU. If the problem is still there it will either come back straight away or before ten cold starts.

Hope you get it sorted out quickly !!!