Need your assistance...

My son's 99 TL has an interesting problem with the idle which only arises occasionally, thus making it harder to resolve.

When he first starts the car, the idle drops down and engine runs rough almost to the point of dying. If he revs the motor or turns on the AC, the problem seems to go away.

I realize it sounds like an IAC valve-related problem, but I replaced that part several months ago when his motor would unexpectedly rev up and down. I have become somewhat familiar with this situation since fixing the exact same problem with my daughter's 99 Honda Accord.

I appreciate any advice and help with correcting this. Thank you in advance.

 

check your wiring for breaks, and cracks. Also check you intake tubing for clacks or loose clamps. I would check your grounds especially the one that bolts to the thermostat housing.

 

you replaced the iacv inside the TB? maybe its clogged already
do you run a name brand 91 octane gas,, always?

the egr port and passage clog too, need to remove intake manifold and clean out every 75kmiles...99s especially bad about it

 

nsnrider,

I will check wiring and hoses next time son comes over with car.

01tl4tl,

Yes, had to take off TB due to location...makes it easier to work on. This is my son's car and don't know what kind of gas he routinely runs...probably not a brand name but would be my guess...whatever is closest and cheapest...which is big problem in Hawaii......high test has not gone below $4 a gal in some time.

I think before removing intake which is big job, I will try and run some SEAFOAM and other stuff fuel system cleaners thru the tank and maybe suck some thru a vac line.

He told me that the problem arises not only when first starting but whenever even when at a stop light.

He thinks it could be a fuel pump problem. Any thoughts?

Thanks guys!

 

Hold it!

If you say you removed the TB, did you replace the gasket? If so, make sure you didn't put it back on upside down (because it fits that way too).

When I was cleaning my TB, I put the new gasket on upside down, and had this exact same issue, simple fix was...flip the gasket right side up.

Here's a picture:



See how it has those gaps, if you put it on wrong, it may cause that idling issue.

 

Oh WOW...yes I did replace the gasket. I will get a replacement gasket before I check that. Thanks

 

just use seafoam - at 2 ounces per gal,,most run 1 can to just under half tank for best results. Do that twice and it cleans all the vac port things plus the fuel system parts,,
if you have any concern over vac port method,,just do fuel twice--
thats direct from the seafoam tech support guy on phone

dont keep adding other things to the gas along with seafoam!

the whole intake manifold removal and egr cleaning is less than 2 hours diy,
at a casual Island pace

 

Yeah after I had that happen I thought I had done something really serious and expensive, and it just turned out to be something that simple.

 

sidenote: that happens with the top manifold cover gasket, when you remove it to remove intake manifold and clean egr system

if flipped upside down, it installs -but blocks a critical passage,, requires
removal and try again

Tip: Alway place gaskets so that everything faces the same way.
face down is a good method - on a clean surface of course
gasket comes off the car and gets set down in exact position

but Im old and need all the help I can get