Jacob11531

Hey guys, have a couple questions hoping that someone can get me some input. I have a 2003 Silverado 1500 2wd with a 4.8 liter bought entirely rust free, great looking truck with 211k miles in Florida. Nothing was done to it but an exhaust and I think the brand was flow master. Over the past 2 years, It is now at 255k miles, I've had intake gaskets put on it and I installed a amazon brand intake for $60 looks like a spectre. Even before I have done anything with it it seemed to have horrible gas mileage than other Silverado's I've driven. Now the truck also seemed to also be very laggy or lazy all the time since I bought it, not sure if something that a code wouldn't show is causing this. I'm wondering if either the exhaust and or the intake are causing my mpg problems, and I'm not stupid yea I know trucks have bad gas mileage. I didn't notice a change in MPG after installing the intake but if I have to put the stock one on I will, I just don't know if its worth my time for no benefit. I will post some pics also.

Thanks,
Jacob

Jacob11531

Craig0320

Your not stupid and that truck should be putting down at least 18 on the hwy. The 4.8 is a turd on a factory tune. Get a tune on it and you will notice a difference. Your truck already had a cold air intake from the factory. It sucked cooler air through the fender well. All that cone filter is doing is sucking hot engine compartment air. Little to no benefit. I installed an air raid intake tube on my factory intake. It deletes the resonator chamber and allows a direct flow from the air box to the intake. Idled and sounded meaner and got 1.5 mpg increase with a tune. You need to look at changing your fuel filter. 03 still had them on the frame rail. My 06 z71 crew cab with 3.73's and 285-70-17's was getting 17.5 mpg on the hwy.

Jacob11531

Ok I will look into a tune just trying to find the cheapest option or diagnosis out there. I forgot to mention that the exhaust was cut back quite a bit because the first winter the salt rusted the crap out of it but nothing else. So to put the picture in your mind, the flow master had a side exit in front of the passenger side wheel. After the first winter the tips were cut from the side exit to straight because they were ready to fall off so imagine the cuts being where the bed meets the van. I didn’t notice any change because over time the exhaust was already rusted in that spot and I also added the intake so from all
that happening at such a slow rate I can’t tell if it used to be better on mpg or the same since I got it. If the exhaust is a big culprit due to no back pressure I will gladly buy a new one. Im sorry I just responded today I never got an email and have been busy but thankyou.

Jacob11531

Also will the fuel filter possibly be my culprit also? Or to some extent. I would say that I’m only getting 10 miles a gallon because I spend $20 every 45 miles I drive and it’s been that way for so long and it kills my pocket

Craig0320

Good lord my 01 2500 with an 8.1 liter gets 11 most of the time and its a 496 bb. Hell I towed 10k last week and got 9 If it is clogged enough it will effect fuel mileage but not that drastically. You definitely have power loss iwth a dirty fuel filter. You have some issues going on to only be getting 10 mpg. That truck should get way better than that. Clean the maf sensor, do a full tune up, plugs, air filter etc.

Jacob11531

Ok I will do that but does the half fallen off exhaust have any reasoning to cause that also? And will it be better to put the stock intake back on?

Craig0320

My 06 dropped 2.5 mps when I installed just the air raid intake. Had to get a tune to get back up over 17 on the hwy. If it was my truck I would remove the intake and try the stock one back out to see if it helps. I imagine it would. Your exhaust is fine. I had not cats and glass packs before on a different one with a tune and no issues.

Jacob11531

So so far my options are to see how much better it runs on the stock intake and if it doesn’t really help much it’s gonna be a tune then right? The exhaust doesn’t have anything to do with it?

Craig0320

No. Stock intake,full tune up, and then see how it does. If it makes you feel better bring it and get the exhaust fixed. You need to have a tune up to get the most out of a tune in your situation.