Surging Or Pulsing When Accelorating

[2_Late_I_Won]

I have a pulsing or surging under hard acceleration in the upper speeds like around 80 mph or so. It almost feels like it's starting or trying to missfire but I don't have any codes or ck engine soon lights and it's only at or around these speeds. Does anyone know what may cause this? I have a 2002 LS 3.9L V8 Thanks oh yeah it has about 83K miles on it. Thanks

[shorod]

Just because you don't have a Check Engine Light (CEL) or stored codes does not necessarily mean you are not experiencing a misfire. If you have access to a scan tool that can read the Component Parameter data, you can monitor the misfire counts on the individual cylinders. The misfire data will be displayed as some number of misfire counts per 200 revolutions. The typical count would be 0, but if you have a cylinder or two that reports in the 10's of counts, the CEL may not illuminate, but you could still feel it in the car.

You could then follow up by monitoring the oxygen sensor readings for the suspect bank of cylinders and watch for a lean or rich condition following a misfire to get a hint at if you have an electrical misfire or a fuel injector that is not functioning properly.

-Rod

[2_Late_I_Won]

Thanks for the response. No unfortunately I don't have access to a scan tool. That is with out having to pay for it LOL. I don't think it's that big of a deal right now to ck into it but then again. I don't want it to cause more problems in the long run.

Do you know if like Pep boys or O'Reilly's has that scan tool that they will check it out for free? I've heard of one of them doing that. Or maybe it was Autozone? Anyway maybe I'll call them to see if they can do that for me and I'll go from there.

Thanks again, Brian

[shorod]

Autozone does have the capability to read the codes, but I don't think they can monitor the component parameters. There is a good chance that Pep Boys and O'Reilly's also will read the codes for free too. It usually requires a little higher end scan tool to monitor the component parameters though.

-Rod

[2_Late_I_Won]

Well I'll try there fist and if it can't pull anything up. I might think about going to a shop somewhere that may have that capability.