Hello,

Been recently having some problems with my 2007 Chevy Cobalt ss, automatic transmission. At start up fine, got the ignition recall replacement, but shift to drive and occasionally there's no speedometer reading, but revs read 2000-3000. After a minute, you get speed and speedometer working, car runs fine.
I've noticed it now idles @ 700 rpm instead of 1000, and there's a slight hum/vibration that comes and goes.
Another non constant issue recently is it is sluggish to get to a higher speed, but evens out. Like slow to go 30 to 40 mph then runs fine, then 60-70 and again evens out.
I've had the transmission rebuilt because of a torque converter slip in the past. I've replaced fuel intake, coils, spark plugs, wires. It has regular oil changes. 180,000 miles.

Thanks.

 

It's not showing any codes when you use a scan gauge? Have you checked all your vacuum lines? Replaced the fuel filter (is this what you called a fuel intake)? Ran some injector cleaner through it?

 

Mine feels the same I ziptied all my ends to make sure they were tight. I have a weak belt tensioner that may be the cause.

 

You may wanna look into to cats being changed. I've changed mine not to far in the distant pass and I'venoiced a considerable difference. Of course it's not going to show a code for that kind of problem but I noticed that it wa a bit sluggish. Now? It's like the car breathe. It goes like hell now.

 

My exhaust is only 4 months old. Zzp 3" short header/dp high flow cat

And resonator