CAR STARTS FINE COLD OR WARM BUT
AT AROUND 1300 TO 2000 PM THE CAR HESITATES. BUT ONLY IN CLOSED
LOOP. AT 2000RPM THE CAR MOVES STRAIGHT THROUGH TO 5500 RPM. RECENTLY STARTED ACTING UP 2 MONTHS AGO.. I HAVE CHECKED EVERYTHING TOP TO BOTTOM. HAS ANYONE ENCOUNTERED THIS PROBLEM. I NEED HELP!!!

 

Does this happen while under load or just when reving it? Is it more common up hills or all the time? Also by hesitates do you mean it only hesitates when you get on it quickly or does this happen when your gassing the car gradually?

(PS might want to check your capslock key)

 

Welcome to the LT1 f-body hesitation experience. You are not alone. Lots of people have fixed this problem, however, not all problems are identical. There is no one fix.

I have been fighting this on my Camaro since I got it (only when warm), although my problem isn't so much a hesitation but a lack of torque with some minor surging. Anyway...

Recently, I've started a tuning project for the car to run 87 octane. One thing I've done so far is turn off Low Octane mode and that has made a rather noticable difference. It still isn't perfect, but it feels better.

Non-tuning fixes that people have used over the years, that I can recall, are:
Opti/Opti harness
EGR/solenoid
plugs
wires
injectors
PCM ground
Vacuum leaks
MAF (replace/clean)
Cross-cylinder compression variance
IAT sensor
O2 sensors

This is all I can think of at the moment. I'm sure others will chime in.

 

-fuel filter
-check fuel pressure/fuel pump

 

I knew I forgot something.

I also remembered two more:
Coil/ground
ICM/ground/temperature

 

My car just today started doing the same thing. It hesitates when you give it gas. You have to pucs the pedal way down, then it surges forward because you have opened the throttle all the way. It does this both from a stop (but not nearly as bad) and from a roll. It is worse going up hills, at which time the car seems to shake. I am thinking fuel filter as a place to start. Other opinions?

Also, in order to release the pressure on the fuel system, what do I do? I cannot find the valve to save my life.

 

That sounds like EGR but it's never a waste to replace the fuel filter.

The fuel rail shrader valve is at the back of the intake, under the cowl. Try not to start any fires...

http://shbox.com/1/fp_reg.jpg

 

The EGR is the Exhaust Gas Recycle and is the thing coming off the exhaust manifold tight? How could it be causing my problem? Does it get clogged or something?

 

my car does the same thing!!!!!!
When I floor it from a dead stop is chuggs along then when the the rpms climb it clears up. Sometimes it does it from a roll and sometimes not. I have a new opti, plugs, wires, fuel filter and coil. tomorrow im going to clean the iac sensor and ill report back.
As far as cleaning the grounds how and where is it done? Where are the grounds and what to clean with?

 

My car does the exact same thing please tell me what this problem is.

 

I changed my fuel filter and it seems to have taken care of the problem...for now. Kevm14, thanks for posting a labeled picture of the intake maifold. It was really helpful.

 

Ok it haappens under load, especally up hills. even when the car is idling in park and I blip the throttle a couple of times it stalls. Then it takes a couple of minutes to restart. I have a snap on scanner with and shows no codes or rally any problems. I have used propane to locate and leaks, including around thwe manifold. Found nothing. i did notice my left bank o2 sensor dipping close to 0 and stay there a few seconds then go back to normal. I bought 2 new ones to install tommorow. but fuel pressure is perfect, sensors have no glitches..hhhhhhmmmmmmm!!!!!

 

i finally got a code today on my snap on scanner. it was code 16 (low resolution pulse faliure) opti-spark. now when i let car idle i punch the pdeal and the car stalls. i think its time for new opti

 

So I just hooker up my MSD 6a box and the hesitation seems to be worse. So I'm guessing that the hesitation is ignition related. Any suggestions?

 

Another thing to check for is fuel pressure. An investment in a fuel pressure gauge is excellent idea for tuning/troubleshooting fuel injected engines.

There seems to be three common reasons for fuel pressure problems that a guage would help diagnose.. 1. Fuel pump non functioning or check valve on the pump not working correctly. 2. Fuel pressure regulator issues. 3. Leaky or unclean fuel injectors.

http://shbox.com/1/4th_gen_tech2.htm...essure_testing

This is a really good article concerning fuel ressure testing.