Hi i have a 99 silverado 4.8L 4x4 regular cab. I have had the truck for about a year now it has 109,000 miles and it just doesnt seem to run right ever since i bought it. The truck came with a dynomax exhaust system already on it and it sounds good when u first start out but after second gear it just bogs down and its like theres no exhaust flow, u have to mash it to the floor to get it going again. I changed the fuel filter, spark plugs and wires, cleaned throttle body, had my fuel pressure checked and everything is fine. If anybody has any ideas let me know, thanks

 

Hmmm....kind of sounds like a plugged up catalitic convertor....or how about the timing? have you checked it lately?

 

no i havnt, i dont know much more than the basics about vehicles...how do you check the timing?

 

also how would you check to see if your cat is plugged up?

 

As far as checking your Converter:

If you have a laser temperature gauge you can call the dealer and ask what the temp range your Manifolds should at when the engine is fully warmed up. Then go out, start your truck, let it warm up, take it out and drive it a few miles, drive it back to your house, and open the hood and check the temperature. If the temperature is above the range it should be, you have a stopped up converter.

If you have a garage or know someone that does, there is an easier way to do this that doesn't require any tools. Start out by letting the truck warm up then again, drive it for a few miles to get the engine hot, then park in a garage, close the doors so its dark, then open the hood or get up under the vehicle and check to see if the Manifolds are orangish or cherry red. If they are you have a stopped up Converter. I have always heard that you can tell (if your good with smell) that if the exhaust fumes coming out of your tailpipe smell like rotten eggs, you also have a stopped up converter, But I'm not 100% sure on that one.

 

thanks for the help ill have to try that out, i think my truck has 2 cats so maybe one of them is plugged up. Hopefully thats what it is because ive been putting it off for about a year now and finally just want to get it fixed

 

Also it will throw a cylinder misfire code if you have not gotten one yet. Its usually the passenger side cat that goes bad.

 

Another thing I should point out is unless one or both of them are really stopped up, you probably wont be able to see an orangish or cherry glow after they get hot. You would have to rely on a temperature gauge. Also, my whole concept is to try and save you some money, if money isn't an option you might just want to take it to your local dealer and have them check everything out.