Car STILL hesitates when engine is warm...HELP! (again)
 

ok, so i had gotten fed up with the ecm and stuff, and dropped the car off at a shop, they fixed it, it starts like it used to, runs like it used to. BUT, i noticed that when the engine temp. is cold, it runs like a beauty! it picks up quick and smooth. but when the engine temp. is hot, it seems to hesitate just a little when accelerating from a stop. Also, the engine seems to hesitate alot more when hitting 30-35 mph, and i ease up on the pedal and it stops the hesitation.
:help:
any thoughts or suggestions will help me out alot!
thanks!

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

and the ses light isn't coming on either when the engine hesitates.(don't know if that helps at all lol)

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Whats the fuel pressure?
Could be the injectors, ohm them.

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Maybe you want to check the o2 and temp sensor, don't think injectors but check them hot and cold to rule them out it's an easy test.

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

ill check the fuel pressure when i get a chance, and post it on here. and during the winter i changed the o2 sensor. dunno if that changes anything lol
thanks alot!

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Sounds like the same thing my car is doing too! Let me know if you find out anything and I will do the same thanks. I give it gas and it hesitates for a sec....

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Being sluggish once hot is typical for the V6 cars, why so many are down on them.

Get the temps under control and it runs crisp n responsive all the time.

a real cold air kit, that takes air from outside the car [ not some under hood open element]

dump the AC rad if yours don't work. [ lets the rad breath ]

make sure your air dam is in good shape.

Get a 180 stats and keep the temps below 200 and enjoy.

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

can someone post a pic of their air dam? lol
thanks

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

check the TPS and when electrical things warm up, resistance is greater, so the throttle position sensor can read ok when cold and then read erratic when warm.

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Update: while driving my car I tried flooring it while the temp was around 180-200, and it hesitated/stalling but didn't turn off. From there to my house the rpms kept dropping while I was accelerating. Fuel injectors ?? Any other thoughts guys. And tomo Im going to try n check the resistance on the tps, and the fuel pressure.
Thanks

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

UPDATE:well had it scanned on thursday, said Mass airflow Sensor was too high, but the sensor isnt that old.
and the car has been idling worse, and died out twice on me?
is the MAF sensor bad? will that fix the idling problem?
thanks!

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Still no fuel pressure test?

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

I think the test port is near the distributor.

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

oh alright, i'll take a look at it either later today, or tomorrow. thanks!

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

The first thing I would do would be to pull the spark plugs and find out just what is going on in the chambers. If you're getting a code 33, your plugs are probably black. Also check the resistance of the temp sensor when warm just in case and of the fuel injectors when both hot and cold. And last, check the film inside the MAF sensor. If the shop or whomever used one of the cheapo parts store sensors, chances are you need a new one already. I've had 2 of them, and neither one lasted more than about a year and a half because neither one was built the way GM MAF sensors are.

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Alright guys Friday morning ill be checking the plugs injectors fuel pressure. School has me busy until then lol. But one I get all thenumbers ill post em here asap. Thanks again everyone!

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

the fuel pressure while the engine was on, the fuel pressure was 40 psi.
The guys at the shop cleaned my injectors with this machine
http://img685.imageshack.us/i/021vcl.jpg/http://img685.imageshack.us/img685/5787/021vcl.jpg

Now hopefully that helps out the car. forgot to check the plugs tho
Can it be the EGR?

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

The problem isn't the EGR, which is closed when the car isn't moving (or should be). If it isn't hard to start and it doesn't misfire when the engine is cold (especially when cold), I'd look elsewhere. It may not hurt to remove the valve and clean the carbon out of it, but, more than likely, that's not your problem. Again, if you're getting the code 33, the problem is probably too much fuel due to a MAF problem. If nobody checked the color of the plugs yet, do so.

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

http://www.youtube.com/watch?v=BTZSevCApeg
Theres a video to the error codes i got.

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Take the MAF out and punt it... It's dead. After the third 1-2 flash, you get 3-3 and 3-4, MAF High and MAF Low.

Before you punt the MAF, disconnect the battery for a moment and find out which of the MAF codes is the actual error and not a history code. It'll be one of the 2 codes. I'm surprised there isn't a code 4-5 as well for rich exhaust.

:edit: Also, when was the last time you replaced the oxygen sensor in the exhaust under the car?

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Thanks alot Maverick!

UPDATE:well in the winter i had my car towed to a local shop, and they had replaced the MAF for me, and i got it back in january. i found the receipt earlier today and i still have warranty. thankfully lol.
Well i dropped the shop a call, and they said bring it by and they'll check it out, so now i play the waiting game lol.
I'll keep updating as i recieve more info

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Update: Well after the shop changing my ecm twice, i got the car back yesterday. When the car reaches around 220*, it doesnt act up until i hit 30+ mph. lol like usual. It doesn't backfire now, but when giving it gas, and then letting off the pedal right away (at 30+) the SES light flashes on then off right away, and it only does that at 220* and going 30+ mph and letting off the gas right away. Also, when coming to a stop while the engine is warm, the idle drops to about 500 and feels like its about to die out.:help:
You guys have helped me out alot, and i was wondering if any of you know what could be causing this?
I just want my car running right, without any problems for the summer :p
Thanks again!:thanks:

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

TTT

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Bump?

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Well thanks again for the help, havent fixed it but as long as it runs, i'll drive it :driving:lol
Thanks alot!

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

still sounds like the maff needs swaping, why did the shop not do that ?

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

Sounds to me like you weren't clear with the shop the problem you were having, or aren't willing to actually pay them to diagnose it. If the car spent any amount of time there they should have figured it out.

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

TIMING!!!!!!!

Re: Car STILL hesitates when engine is warm...HELP! (again)
 

I don't know. it still looks like the same ac delco one they had put on before.

No i paid them lol, and i used to go to them all the time, but they just kept charging me for nothing. and i even wrote down the problems the car was having and gave it to them when i dropped off the car. it spent a while there, they said they dont know whats wrong they swapped the computer again, still didnt know.