OK I\'m Hacked. MPG stuff. Ok so most of have read my burb thread. I'm getting 10 mpg in a 454 burb with TH400, 3.73 gears and 31 inch tall tires. Engine has 72k on it. It has been maintained fairly well by the PO. The MPG is true. I verified the miles with my GPS so it's not odometer error. Now everybody here says 10mpg hwy is normal. Well I think there is more and here is why. I also hang out on a RV forum for Airstreams. These guys with 27-31ft 16,000lb motor homes are pulling 11-12 on the hwy with CARBS and I should be able to pull at least that in a vehicle with the same engine (with FI) and tranny and 10,000 less pounds! Ok I'm going to see what I can do with it. I want 14mpg hwy. I know people that were pulling 18 out of 350 FI 4x4 1/2 ton burbs. I think it has 14 in it. The truck Managed 9mpg with 7500lb of K5 on a trailer behind it with 4 bad plug wires. What has been done to this point. New cap and button Wires O2 sensor plugs. I have a serge I'm chasing at hwy speeds. I am really starting to believe it's a bad Cat. Plugged cat can explain several problems I have. The truck has a heat up problem at idle with the A/C on. Truck shifts really hard at times. BOTH exhaust manifold gaskets are blown and blown bad. It all can be explained with excessive back pressure. If the engine can't get rid of the exhaust it's going to cause low intake vacuum. Low intake vacuum will cause misreading of the MAP sensor as well as incorrect readings for the O2 sensor. This will get it into a visious cycle and possibly cause it to run rich and further plug the cat. Low manifold vacuum will also cause the transmission to think that I'm using a lot of throttle (TH400 no electronics on it all works with manifold vac) and it will firm up the shifts thinking it's under a heavy load. Here are my plans for this weekend. Finish tune up. I haven't had a chance to set timing and install a PCV. I also want to check every vac line on the truck and check for vac leaks at the throttle body. Rig up the truck for testing including a Vac gage I can read while driving. Add some pig tails from O2 sensor, Map Sensor, TPS and run them inside so I can monitor them with my VOM while driving. See if I can round up a Lap top and down load some EFI monitoring software. I'm going to try to find a peice of 3 inch exhaust pipe and pull the cat. Run it for a week without it and see what changes. Then I'll get a Free flowing Cat to install on it and we can see how much a cat eats. Change over to Full synthetic motor oil as well Now the point of this thread is for me to hear some of your ideas to try a few and for me to share the end results. I also want to hear some results of upgrades and products others have used to try to make some MPG and performance gains and see their results. What I plan to do is a tech write up for the site and see what results I can come up with. This will take a couple months at least but the hope is to provide some good solid information for others. I plan do do this in steps so I can run at least 150miles after each change to get some good MPG figures. That's roughly a week between each change I try. This will lead up to part of a build up of my Ultimate tow rig. We (My family) plan to do some cross country traveling with our camper. This is what this truck was bought to do as well as serve as my DD. So like many of you this truck is serving multiple needs. Some things I am investigating is a bolt on over drive if I can swing it. Also looking at some ignition upgrades. Maybe a Jacobs or MSD set up. Ok, lets hear some ideas? What sort of upgrades would you like to see some tests on and I'll see what I can do about providing them. What products have you used and what are your results with them good or bad.