Strange sound

[dannmarr]

While driving up hill I feel a stuttering, thumping, choking kind of sound. This happens only when I excellerate quickly up hill. This does't happen from a stand still, it happens when I let go of the gas to slow down, then press the gas to excellerate. The speed or the RPMs dont change while I feel it. If I press the gas slowly, it's smooth. Could it be the regular gas I've been using? Dirty injectors? Anyone had this experience?

[1986nate]

Putting regular gas can cause the ECU to retard the timing but wouldn't think it would be that bad...Also how many miles as possibly could be due to a cat converter going bad... but again that would probably do it from stand still as well...

[dannmarr]

I just hit 190K. The converter is about 2 years old. I'll check my codes.

[log1call]

Sounds like the symptoms, "I feel a stuttering, thumping, choking kind of sound", should lead to it really. Wish I could drive/hear/feel it.
A miss doesn't cause those symptoms, nor does a fuel blockage really... well not unless they are really bad missing or fuel blockages. Have you done a tune up? Plugs, air and fuel filter?

[SoCal LS-L]

Sounds actually like misfire or preignition. You ARE using 91 octane right??

[1986nate]

Originally Posted by SoCal LS-L

Sounds actually like misfire or preignition. You ARE using 91 octane right??

nope, he said he's using regular...

[SoCal LS-L]

Ahhh well priority one should be fill up with 91 octane and see if it goes away.... sometimes knock sensors dont work and wont retard the timing, resulting in the detonation you may be hearing. Yikes using regular 87 in a SVX is borderline criminal !!

[dannmarr]

I filled up with Premium and the noise went away. I guess that's what 'knocking' sounds and feels like. Thanks for the inputs.

[SoCal LS-L]

Splendid Hopefully this knocking business did not go on too long. Your knock sensor must be dead, it should have given a signal to the ecu to retard timing. Shouldnt be a prob now just keep the 91 proof flowing.