Newbie with a problem

**HasselZ28** · 10-31-2007, 05:04 AM

Hey well this morning I noticed my Z is acting strange. So I'm going to try to explain this as best as possible. Yesterday I did a some "spirited driving" on the highway with a GTO and had no problems car ran great. This morning I got in her to go to work, she started up fine and was driving fine, untill I was on the highway and I noticed that when I was in cruise or coasting and would hit the throttle there was a little hesitation and then you could feel the car accelerate, there were no noises. I did notice it after I got of the highway also. Now as far as the modifications I have done on my car the go as follows, FRA, 3.73 gears, superchips programmer, sea foam about 2 months ago (in which I have gotten oil changed after 200 miles of doing it). I have not done the fuel filter. Now I have the shift pressure all the way to the max on the programmer, but it doesn't seem like a tranny issue, I'm kinda stumped, and want to diagnose this early so it doesn't get worse. All help Is appreciated, Thanks.

**HasselZ28** · 10-31-2007, 05:17 AM

ttt

**sunsetorangess** · 10-31-2007, 07:23 AM

Its a shot in the dark without any info. I would drive it a few more days and see if anything Happens, Ie Throws a code. In the mean time just look over the motor, make sure nothing came loose or looks iffy.
J

**HasselZ28** · 11-08-2007, 08:51 AM

Still doin it ttt

**B34M3R** · 11-10-2007, 04:56 PM

Like he said... huge shot in the dark...

It could be fouled plugs... the fuel filter... sticking injector... your chip... just about anything.

When the problem is that minor... it could be any number of minor problems. Sorry, but I can't think anything overly helpful.

**jigger1166** · 11-11-2007, 06:42 AM

How long has it been since the fuel filter was replaced? If it's been a while, check your fuel pressure. Maybe the filter's plugging-up, or the fuel pump is going bad.

**HasselZ28** · 11-12-2007, 08:20 AM

Just replaced the fuel filter, checked spark plugs, cleaned throttle body, cleaned MAF sensor still doing it. I'm stumped.

**ggino85** · 11-12-2007, 08:29 AM

how long have you had 373's

**02bluez28** · 11-12-2007, 08:58 AM

Originally Posted by HasselZ28

Hey well this morning I noticed my Z is acting strange. So I'm going to try to explain this as best as possible. Yesterday I did a some "spirited driving" on the highway with a GTO and had no problems car ran great. This morning I got in her to go to work, she started up fine and was driving fine, untill I was on the highway and I noticed that when I was in cruise or coasting and would hit the throttle there was a little hesitation and then you could feel the car accelerate, there were no noises. I did notice it after I got of the highway also. Now as far as the modifications I have done on my car the go as follows, FRA, 3.73 gears, superchips programmer, sea foam about 2 months ago (in which I have gotten oil changed after 200 miles of doing it). I have not done the fuel filter. Now I have the shift pressure all the way to the max on the programmer, but it doesn't seem like a tranny issue, I'm kinda stumped, and want to diagnose this early so it doesn't get worse. All help Is appreciated, Thanks.

I have the exact same car as you, slightly diff mods tho... I had the same problem not long afer I used sea foam...I thought I might just need new plugs, but I never figured out what it was...

**HasselZ28** · 11-12-2007, 09:11 AM

I've had the 3.73's for about 2000 miles. When I seafoamed I didn't notice the hesitation afterwards. Actually since I've bout it it has had pretty much the same hesitation but now it seems a little worse. I'm contimplating getting the injectors cleaned but thats $150, alot to spend with not knowing if it will help.

**ggino85** · 11-12-2007, 11:55 AM

hassel, i just got to say ur aviator cracked me up

i have felt like that, on more than one occasion with my car.

**jigger1166** · 11-12-2007, 03:36 PM

Originally Posted by HasselZ28

Just replaced the fuel filter, checked spark plugs, cleaned throttle body, cleaned MAF sensor still doing it. I'm stumped.

Check your fuel pressure.

**jigger1166** · 11-12-2007, 03:40 PM

From the pages of GM Service Information

Document ID# 683183
2002 Chevrolet Camaro

--------------------------------------------------------------------------------

Hesitation, Sag, Stumble
Checks
Action

DEFINITION: A momentary lack of response when the accelerator is pushed down. The condition can occur at any vehicle speed. The condition is usually more pronounced when the driver first attempts to make the vehicle move, as from a stop. If the condition is severe enough, the engine may stall.

Preliminary
• Refer to Important Preliminary Checks Before Starting in Symptoms - Engine Controls .

• Search for bulletins.

• Inspect the powertrain control module (PCM) grounds. Ensure that they are clean, tight, and in the proper locations. Refer to Engine Controls Schematics .

Sensor/System
Test the MAP sensor operation.

Fuel System
• Test for incorrect fuel pressure. Refer to Fuel System Diagnosis .

• Test for a restricted fuel filter. Refer to Fuel System Diagnosis .

• Test for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

• Inspect both injector fuses for being open. An open injector fuse causes 4 ignition coils and 4 injectors to not operate. Replace the fuse. Inspect the ignition coil circuits. Iinspect the injector circuits for an intermittent short to ground.

• Test the fuel injectors. Refer to Fuel Injector Coil Test .

• Inspect the items that cause an engine to run rich, with a long term fuel trim near -13 percent. For a rich condition, refer to DTC P0132 or P0152 .

• Inspect the items that can cause an engine to run lean, with a long term fuel trim near 24 percent. For a lean condition, refer to DTC P0131 or P0151 .

Ignition System
• Wet the secondary ignition system with water from a spray bottle. Wetting the secondary ignition system may help to locate damaged or deteriorated components. When you apply the water, look and listen for arcing or misfiring.

• Test for proper ignition voltage output with spark tester J 26792 . Refer to Electronic Ignition (EI) System Diagnosis for the procedure.

• Remove the spark plugs and inspect for the following:

- The correct heat range

- Wet plugs

- Cracks

- Wear

- Improper gap

- Burned electrodes

- Heavy deposits Refer to Spark Plug Inspection in Engine Electrical.

• An improper spark plug gap causes a driveability condition. Gap the spark plugs using a wire gauge gap tool. Refer to Spark Plug Replacement in Engine Electrical.

• Before you replace the spark plugs, determine the cause of the fouling.

- Gas fouling--Refer to DTC P0172 or P0175 .

- Oil fouling--Refer to Oil Consumption Diagnosis in Engine Mechanical-5.7L.

- Coolant fouling--Refer to Loss of Coolant in Engine Cooling.

Engine Cooling System
Inspect the engine thermostat for proper operation and for proper heat range. Refer to Thermostat Diagnosis in Engine Cooling.

Additional Checks
Test the generator output voltage. Refer to Diagnostic Starting Point - Engine Electrical in Engine Electrical for the procedure. If the generator output voltage is less than 9 volts or more than 16 volts, repair the charging system.

**01blackbird** · 11-12-2007, 07:41 PM

Now that's a lot of good info for you. A common item that can cause your problem too is the TPS. If you know anyone that has a scan tool do the sweep test and check for anything that looks out of place. Ever since 1996, GM V-8's are very sensitive to fuel pressure, so yes pressure is very important. Have you tried to put the factory computer settings back in just for the hell of it?

**HasselZ28** · 11-13-2007, 04:40 AM

Wow, well thanks guys, for all the help and feedback. I know this isn't an uncommon problem and is hard to diagnose. Unfortunately I do not have the right tools to check my fuel pressure, TPS, and ect. I have returned the vehicle back to stock to see if the problem presists, and it does. I think I might just have to bite the bullet and take her in, but its not a big problem she still drives like a dream, she just has that hesitation on the highway and I am a perfectionist and want her to be 100%. I have some mods I'm going be doing this winter (headers, possibly cam & heads) and when I do that I'll be able to look at more and also get a proper tune. So thats kinda where I'm at.

**01blackbird** · 11-13-2007, 06:27 AM

Good luck on your direction and hopefully everything goes all right.

**QKSLVR99** · 11-15-2007, 06:09 PM

had sim. problem after i did sea foam treatment also, think it was a combination of things, seafoam still working a bit, factory O2s with about 90k on them, and a pain in the ass #8 plug wire. Changed o2s, and got new wire and haven't had a problem sence

good luck