Hesitation during acceleration.
 

I have a 2000 Camaro SS I purchased used from a local dealership about 3 months ago (81k miles, 6 Speed Manual). While driving around town I've noticed a tick or hesitation in acceleration always at 2500RPM. The hesitation isn't always there but when it does happen it is always at 2500RPM right on the dot. I had the oil changed with Mobil 1 from the local Chevy dealer, I replaced the air filter with a new K&N and I ran a bottle of Sea Foam fuel injector cleaner through it to no avail. I've used nothing but Exxon 93 Octane gasoline in it since I got it. The dealership I bought it from had done a lot of work to it before reselling it which kinda makes me worried (Rebuilt rear end, Door bushings, both belts and the upper auto tensioner pulley). I have purchased a new AC Delco fuel filter but haven't had a chance to install it yet. The Chevy dealership where I got my oil changed at said I needed a throttle body cleaning and that I should have one done every 30k miles but I couldn't afford the $200 price tag. Any ideas as to what could be causing my issues or at least where I should start?

Buy some throttle body cleaner and clean the tb yourself. It's not that hard to do.

I had thought about cleaning it myself but I'm new to this whole fixing cars thing so I didn't want to mess anything up or make it worse. Do you think a dirty throttle body could be causing the hesitation problem? Is it a commonly known issue on these engines? I know it's apples to oranges but I had a Nissan pickup truck that went 145k miles without ever needing to have the throttle body cleaned.

no offense, but that is comparing apples to leather shoes...

if you never pushed on your truck, never drove it sporty, or let the air cleaner get dirty you wouldnt have to clean it.

The trottle body on these cars does get dirty. very dirty. because we play with them. throttle body cleaner is under $10 just buy the cleaner and do it yourself.

as for the hesitation. there are multiple things it could be. start ruling them out.


change the fuel filter.

clean the throttle body

if its still there check your plug wires: loose cracked freyed or dry rotted needs replaced (id go ahead and replace them and the plugs)

after that look at your spark plugs (seafoam can foul plugs sometimes)

then check your fuel pump.

then check your throttle position sensor

then check to see if the timing is off somehow (im not sure how that would work)

did u hear any sound like tick tick tick when u puch on the peddle ?

have it scanned for trouble codes and if it has the ability to read info while running then while scanner is handy take the car for a drive, it would be best to have a scanner hooked up and be watching whats goin on while the issue is in progress. need to test the throttle position sensor. its one thing that could fail at a certain throttle position. doing it at a certain rpm is an odd issue, i would think the cam/crank sensor could do it.

Sorry for the delay in response I have 3 small kids and they don't leave me with much free time.

I don't hear any ticks when punching the peddle.

I don't get any check engine lights or anything like that.

I have noticed that the problem doesn't seem to exist until the engine gets up to operating temp.

I plan on doing the throttle body cleaning and fuel filter this weekend. Any recommendations on brand of cleaner? A lot of people recommended the seafoam fuel injector cleaner so I'm leaning towards the seafoam TB cleaner.

I separated a statement you made so it stands out

where is the choice for C: none of the above

you have a closed loop issue when all of the sensors are active and the computer is making adjustments based upon the readings


without any diagnostic gear on your car it's just a guessing game

you can do the things you mentioned as preventive maintenance but they won't fix your problem

My suspicion would be toward one of the O2 sensors. You can go buy new ones and take a crap shoot (if you have stock exhaust they are a bear to replace) or you can get the car diagnosed at a shop which has the equipment.

Or, if it's that intermittent, live with it. My 4th gen has been running terribly rich for a few months but it's coming off the road for a week and I'll slap on new O2's then.

My car is about as stock as you can get including the exhaust. Not being a real mechanic I feel that replacing the O2 sensors would probably be way over my head. I priced the O2 sensors at about $90 each for a AC Delco from O'reilly. I'm not sure how many O2 sensors the car has but at $90 a pop that's an expensive guess. Sounds like I'll have to take the car in to a mechanic to have it looked at. I still plan on doing the TB cleaning and Fuel filter this weekend as I'm not sure when they were done last and like you said it's good maintenance. It's good to know going into it not to get my hopes up. I appreciate the help.

Like Torque said this is a closed loop drivability issue. It is one of the tuffer issue to track down and would get you an A grade mechanic along with an A grade hourly price at the Dealership. $200 to clean a throttle body? That is just rape no matter where you are in the Country. You can have the whole intake off the car cleaned and back in place in less than 2 hours. The first thing that comes to mind on your issue is a dead spot in the TPS or a MAP sensor with a bad spot. It could just as easily be O2 sensor or a EGR valve sticking. I don’t see the TB cleaning fixing anything in the 2500 RPM range but these do need cleaned. Dirty TB will normally cause shaking or even stalling at idle along with long crank times.
You need to find a good Mechanic you can trust. This will not be guys working at some chain store. This will be some guy who maybe did a few years at a dealership or is really a fast learner. Good mechanic are not normally great business men so they can be hard to find. Go to car shows or cruises and talk to guys with LS1. Somewhere near you is a LS1 expert that just want a fair wage and he knows your stock setup inside and out.