Putting noise and horrible performance

[Joeboxster]

It is running like crap....It's putting like a backfire noise but more of a putt putt noise from the exhaust.... it's running very rought at anything below 2000 rpms....I noticed when it is cold in the morn it runs fine as soon as it warms up the idle drops from around 7-800 rpms to between 6-700 rpms & that's when the fun begins...it becomes very sluggish i almost got blasted making a left turn it wouldn't move fast enough...soon as the rpms go up it takes off and runs smooth...then it will backfire sometimes when it is downshifting...any help would be greatly appreciated....could it be the maf sensor..
Thanks, Joe

[mikefocke]

Model year?
Mods?
Miles on engine?
Using good gas?
How long has this been happening?
Anything done to the car shortly before first occurrence?
CEL? Codes?

[Wayne 962]

Right, what Mike said. Without knowing the codes, then you're just shooting in the dark. A non-functional mass air flow sensor (MAF) can cause running issues, but these sound a bit more severe than the typical ones associated with a bad MAF. It may be a big vacuum leak somewhere too. If you wish to go the cheapest route first, I would remove the engine compartment and just take a look at the engine to see if you see any broken or disconnected hoses, or a disconnected or cracked boot attached to the throttle body. The problem may be obvious and won't cost you a dime to diagnose. After that, I'd get the codes read and see what they say...

-Wayne

[Joeboxster]

2000 Bosxter with a 2.7 with tiptronic..... engine was replaced there is only 20,000 miles on this one...It just started happening about a week ago.....I tried adding fuel injector cleaner to the gas the last two tanks full with no improvement

[mikefocke]

So no mods, no CEL, no codes?

Any maintenance done on the plastic parts like the AOS or oil tank or coolant tank? Done any simple things like looked at the air filter, inspected the coils, inspected the throttle body?

[Joeboxster]

no to all of the above.....i visuall checked everything with my truck mechanic everything seems ok besides a dirty air filter..he said i need to do a test for vacuum leaks with smoke?....also he didn't have his tool to remove the maf with him it was at his shop....does this seem like the correct course of action?.

[Wayne 962]

Again, I would get a code reader and read what the car says is wrong with it.

-Wayne

[Alphaboy1]

I would listen to Wayne, JP and these other cats!

[Joeboxster]

Thanks Guys..