Ok so i will try to make this short. I just took my car in last Monday because it would loss all power whenever you tried to accelerate. It will drive fine until you try to accelerate onto a highway. Normally acceleration is fine but when it gets to around 3 1/2 to 4 grand it drops to 2 grand then the car will slow down and then all of a sudden it will pick right back upthere have check the car over and over they put a new computer, all kinds of new sensors and have been on line with chevys main tec department for three days.

Now they are telling me they might have to ship the car somewhere to get it fixed. but nobody can find out whats wrong with this thing. So if anyone has had a problem like this please let me know.

 

i had a kinda similar issue like this but when i would floor my car it would struggle alot and it would just turn off on me and trust me this was bad. problem to this was the crankshaft sensor. the wiring was just hanging by a thin piece of cable. so i fixed that and all the problems were gone. try checkin there. or could be the sensor it self...am just giving suggestions...

 

This problem sounds a little familure...
When I was in A&P School to get my aircraft mechanic certificate,
One of our projects/classes was on Piston engine troubleshooting.

A Similar problem came up. When the engine was reved up to a high RPM,
it would drop down to a lower one, then go back up higher and kind of bounce.

Problem was a weak/broken valve spring. This lets the valve to float, and the
effected cylinder drops off power. Once the RPM is lower, the valve stops floating
and the cylinder recovers. Keep in mind if a valve is floating, it could be damaged
by the piston and the piston could be damaged by the valve.
You should be able to get to the valve springs by removing the valve cover. A Haynes and Chiltons is a must if your going to do it yourself. Before you pull off the valve spring, stick some rope down the sparkplug hole and turn the engine by hand until the cylinder comes up on compression and pushes the rope up against the under side of the valve. This will hold the valve inplace and prevent it from falling into the cylinder.

To find wich cylinder, youll need the assistance of a friend. Have him set the engin RPM up to like 4 grand, where it and take tempature readings on the exhast before the manifold. Look for a cold exhaust. Or you can just change out all sixteen springs. If ones worn the others might be worn too. Might want to borescope the cylinder to make sure the valve and piston didn't get into an argument though.

 

oh god. i hope you dont have valve train issues. that would blow!

 

It just hit me,
Spark Blowout!
Check your plugs, get them gapped and cleaned, or replaced.
Higher RPMs and Higher cyilinder compression pressures can
cause the spark plugs to fail to spark. Some aftermarket tunes
require a diffrent then stock gap setting because of this.

This Also just hit me:
Check the codes. I'm sure you'll have misfires.
Depending on the code can tell you what cylinder
the problem is in, if its spark plug or valvespring.

 

See thats the thing it is NOT throwing any codes. the check engine light doesnt even come on. i talked to them around 4 and they changed the computer out AGAIN and they said it fixed it for about an hour and then they took it out for a drive and it all started again. so now thats two computers, a fuel pump, they checked all the spark plugs, and have change a dozen or more sensors. my car is gonna be pretty much brand new if they ever do fix it.