2002 Chev Impala - 3.8L Power Loss

[mtkauto]

2002 Chevrolet Impala LS with a 3.8L (VIN K) -

I have power loss at acceleration (or under a load) and initially repaired a faulty fuel pump. The pressure was at 45psi KOEO and should be 53- 59psi. I now have good fuel pressure and I replaced the fuel filter but the engine acts as if it is restricted. Similar to when a cam sensor is bad and a car would want to stall but it does not. At idle it is fine. Is it possible for the converter to be bad and not throw a code? There is no DTC's to work with.

My other thought was if it could be a Crank or Cam sensor...

[ricmorin]

What are your fuel trims when it acts up? That should determine if it's fuel or something else.

[steven kiser]

yes, it's possible for a cat to be plugged and not throw a code. actually it's fairly common. in my shop we take out the 02's and run it. you should notice increased power if the cat is restricted.

[liljoe]

yes, it's possible for a cat to be plugged and not throw a code. actually it's fairly common. in my shop we take out the 02's and run it. you should notice increased power if the cat is restricted.

Use caution on this, had another tech in th shop one time take them out and go on test drive around block. With all the exhaust comming out the sensor holes, it got hot enough to melt a good bit under hood wire harness. Just make sure to look where the hot exhaust stream is going to go. I would be looking at the MAF readings on this as well....

[brianp87]

Back pressure test i knock a samll hole then weld it up or put a screw in it tell cat is fixed.

[jbadenoch]

sounds like clogged cat or maf. this would be a good time to use your exh backpressure tester. If it does have a clogged cat you should also make sure vehicle runs good and tune-up parts are correct and good before replacing cat

[Stewart Levy]

Has anyone tested the timing chain!