randomTL

Tryin to figure out what the heck this may be. I have a 99' TL. I'm not getting any check engine lights, but the problem is slowly getting worse over the past year. Here goes. It seems to happen mostly when the car is cold or warming up but when I accelerate from an idle the more gas I give it the more it hesitates. Also, when I turn a corner I let off the gas to brake, then try to accelerate and it wants to hesitate. Seems to idle fine, and after initial hesitation it runs great all the way to redline. When it warms up it doesn't seem to do it near as much. So far I have replaced plugs, o2 sensors, MAP sensor, cleaned intake, and EGR port, and run tons of fuel injector cleaner including directly into intake at oil change place. Without any CEL lights I don't know what else it could be. BTW it has 112k on it. Any ideas? Thanks.

fsttyms1

Have you checked your ground wires? reset teh computer?

sbuswell

I agree check ground wires, when I changed mine my car didn't hesitate as much.

wilp99

fuel filter..

phipark

Tps?

phipark

No, are fuel filters are in the gas tank and aren't really serviceable.

randomTL

So what do you mean ground wires? The cable that goes from the ground of the battery to the chasis and from the motor to the chasis? I did reset the computer, no change, and there is no fuel filter on these cars. There is a fuel screen in the gas tank but you cannot replace or access that without replacing the whole fuel pump because it is built-in. My father-in-law who is a mechanic said first thing that it might be the TPS sensor, but that also is somthing you can't replace. According to dealer it is "lifetime" and the only way to replace is by replacing the whole throttle body. Lots of $. Thanks for the suggestions though. I will look at the ground wires. Also, if this helps, I have noticed some black around the exhaust tips, and when I come to a stop I can smell the catalytic smell from the tailpipes, which leads me to believe it is one of the sensors...

sbuswell

possibly your cat is extremely dirty and air is not flowing as freely as normal. I would change grounds. batt/chassis, batt/block and see if that helps. I know the ground from batt/block on my car was exposed and frayed badly. my car responded well to changing those grounds to 4ga.

randomTL

Ok well now I have changed my ground wires to new 4ga, replaced coolant temp sensor, reset the computer, and it is still doing it. When I step on the gas from a stop it just chokes and sputers for like 1.5-2 sec then accelerates strongly. Really bad when cold, and better when warm. Could it be the EGR valve that is screwed up even though there is no check engine light? Really don't want to have to take it into Acura but I'm not having much success troubleshooting on my own and these dangs sensors are expensive.

wilp99

seing that the tranny uses the tps as one of its primairy sensors, i would count that out. unless its shifting at different points than it was before the problem. there is an intake air temp sensor that works as a mas airflow sensor (kind of).. could be the problem.. thats where my guess would be at.. maybee cracked vaccume line somewhere.

acurabum

It looks like your TL run to rich ( to much fuel..not enough air ) while
warming up.!!! What is the RPM after starting ? and when in D5 while hesitate?
Did you check your air filter ?

acurabum

Sorry , forgot to ask you if it only happen when it rain and humide or all the time
and when did you change your plug ?

joseph_99tl

i had the same issue and i replaced the IAC valve.

on the throttle body.
fixed.

the dealer told me they sell alot of them to service stations.

bkzjimmy

what is that?? and did u change it?

did u di this all urself....if not, how much $$ did it run you?

bkzjimmy

what is that?? and did u change it urself?

did u do this all urself....if not, how much $$ did it run you?

joseph_99tl

it's about a 200.00 part.
do a search....it'a a fairly common issue.
i did it myself.
it is easy.

joseph_99tl

picture in this thread

https://acurazine.com/forums/showthr...ighlight=valve

part number 2

bkzjimmy

thanx

randomTL

Air filter is new K&N less then 2000 miles on it, plugs were changed at 105k now at 112k and they are NGK platinum. I will look into the IAC valve. I looked at the IAT sensor and it seems to be fine. Temps have been in the 40s and 50s and humidity has been 80-100% everyday for the last 3 months, rains nearly everyday here (Oregon). RPM is around 1200 when starting cold, feels just slightly rough, not bad though. When warm is settles to around 750. I don't really think it is a vacumn issue because there is no surging, in the RPM and idle is very consistent. I do think it is running slightly rich, but it feels like there is no gas when you really step on it from stop. Thanks for all of your suggestions.

joseph_99tl

the IAC valve is actually a little motor.
there's no way to tell if it functioning just from looking at it.

randomTL

did u do this all urself....if not, how much $$ did it run you?[/QUOTE]

I had my 105k service done (timing belt, plugs, water pump, etc.) at a Honda Acura specialty shop, but all of the other sensors and the intake cleaning I have done myself. My father in law is a mechanic so he can get the parts for me at a discount. O2 senors were $70 front, $50 back, map sensor $30, coolant temp sensor $35. Nothing real outrageous, they just add up. I think it you have the slightest mechanical inclination you should be able to do most of this. I had the shop do the timing belt and water pump though, because I really don't get that into mechanical work. Now, that I am kind of at a dead end as to what it may be I will probably just take it in to the dealership instead of wasting time and money on parts that don't solve the problem.

PenancE

r u blind? look at the posts above.

crombie1000

I just wanted to toss you a line and tell you that my car experiences similar problems. When I am driving along at 30-35MPH in D5 my car will basically feel like it tries to stall out for just a second. the rpm's basically drop almost to the peg and pop back up in about 1/2 second. I dont know if its the transmission bogging the engine down or the enging dropping out. I took it to acura and they told me it was basically my immagination. I am VERY unhappy with their service. I am only able to reproduce the problem when I am neither accelerate or decelrate in the 30-35 +/- a few range. I drive under 2 miles to work and it will only happen on this short drive. I'm not sure if this is the same problem you have? But like you, when I step on the gas it will drive very hard all the way to redline. The drop only developes during a slow drive speed. I dont mean to hijack your post, hope my info helps, but if anyone, or you can help me. Let me know. Good luck!

PenancE

tune into this post i got same issues.

i guess u cant REUSE the IAC?

gotta buy brand new eh?

PenancE

ack found it, yea u can.....maybe ill do this later on today,,,,,takin the IM was so ez.

sbuswell

I do not believe you can reuse(did you mean clean) the IACV. I believe you have to replace it. It seems to be a very easy DYI. I have never had to replace mine, but it looks easy. Anyone having idle problems should be looking at the IACV as the culprit first.

randomTL

I don't see what the IAC control would have to do with what I am describing. I do not have idle issues, it idles fine warm and cold. The idle is smooth and right where it is supposed to be 1250 when motor is cold, 750 when it is warm. It is an acceleration issue. When I accelerate slowly - no problem, when I step on it it blogs down like it is not getting any gas. Sometimes it happens when I turn a corner and go to step on the gas again as well, engine bogs down 1-2 sec then picks up and upshifts. It does not happen all of the time, just like 25-30% of the time. I really don't think it is a tranny issue, definately a fuel delivery issue.

wilp99

sounds like you have it all figured out then.. youve rejected everyones suggestions, and have troubleshot it down to a fuel problem.. and since the iacv is like a choke on a carburator and has absolutley nothing to do with the way a car idles we are all wrong. good luck.. and i still think its the intake air temp sensor.

sbuswell

One last suggestion is to sea foam your engine(oil tank, gas tank and thru vacuum or brake booster line) that may help. Could possibly be a failing injector or extremely clogged one.

03CoupeV6

Oh this could be anything. The IAC valve could be it, but I don't think it's a fuel delivery issue.

This could very well be a transmission issue - it can bog the engine down. It just sounds like you've checked and kept the engine in good shape and therefore I'm more inclined to look to the transmission behavior.

randomTL

I thought I would post this update for anyone that may be having the same issues as I did. I finally called my service manager at the Acura dealership to see if he had any ideas on what might be wrong with my car. He said it had all of the classic symptoms of clogged fuel injectors and recommended an injector cleaning. I decided to go ahead and do it, because I trust what he says. Basically what they do it disconnect the fuel pump and run high pressure cleaner directly into the fuel rail for about 30-45min. Afterwards they have to replace the muffler gasket and several washers because of the corrosiveness of the cleaner.

$185 later, my car is good as new. No hesitation, and the power feels like it did when I bought it. So as I said in my last post, I thought it was a fuel delivery issue and it was. BTW he also said that during the past six months they have had tons of fuel related problems on Acuras. He asked where I bought my gas, and I said I used to buy Costco gas (premium of course) but have now switched to Chevron and/or Shell. He said good, because everyone using Costco or cheap gas has had these kinds of problems. Apparently Acuras are more prone to problems using cheap gas. Moral of the story, spend a few cents more and give you premium car - good quality premium gas.