NO codes... ran 14.8 at 90 mph 6 months ago... slowly is gettin slower... i ran 15.3 at 87 last nightlast night .... only things ive changed it went to new plugs and taylor shorty wires. I have 115k miles... anything i should check? Now when i ran 14.8 i had new tires and it was 30 degree's cooler... 5/10th is a big gap...anything i should look for... it seems like i loose my power after 2nd to 3rd gear shift? And a little offthe line cuz my 60 fts went form a 2.1 to a 2.3.

 

try Sea Foaming your truck, 115K does a lot to a motor.

 

I know this may not be it but how full was your tank on fuel on both runs. If it was almost empty on the 14.8 and full on the 15.3 it may be a few of those 10ths. 20 gal of gas weighs about 122lbs.

But like said before 115k miles can leave lots of garbage in engine. Do some cleaning and check again. If that does not help then it may be any upgrades you have done since the last run.

 

Part of that difference could be caused by the different blends of gasoline. Summer/Winter blends, different companies, etc.

 

Only change was taylor shorty wires and new plugs... gapped .045... my old plugs had almost a .070 gap lol I'm putting a brand new set of mopar wires on my dodge tonite. I wanted to get back toa 14.8 or close before i put the cam/headers i have for it. Just to see the real gains.

 

I have run 7/10th of a second difference between winter and summer. Weather makes a huge difference in performance!!!

 

30 degrees is huge!

 

winter is better than summer for racing/times.