Does anybody elses truck seem like this? Some days it'll run like a scalded dog, then others, it feels like a slug. Not much has change in those days, air temp, humidity, etc.. I've driven to the store and it seems to run strong, run in the store, come back out to go home and it's seems to run different 10 minutes later. What gives?
Jim

 

hehe you're not the first to post a similar thread. Somedays you just feel it, somedays you don't. Hard to explain really.

temp, humidity, blah blah....in Houston it varies so much at times its hard to tell.....From 90 degree humid summer nights to 30 degree crisp winter nights, with such changes, you learn to feel the difference.

 

the ecm's are too damn smart sometimes! they are constantly learning driving habits, conditons, etc. if you shut it off on a day that it is nice and the next day it is crappy, it is trying to compensate for the difference in atmospheric conditions and so on, this is probably what you are experiencing.

 

ya, mine does the same. pisses you off on those days. fun truck to drive though. i live in upstate NY where the temp has extreme fluctuations from day to day. the other day we got a heat wave (like 50*), and then today it was close to single digits. man what a difference in ***** my truck had today. ah, no need for NOS up here in the tundra <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

yep, the engine gets more oxygen in colder weather. They are programmed to increase/retard timing partly based on the temperature of the air as it passes through the MAF. That is why some people put in resisters on the IAT wire (less voltage = colder temp) to trick it into giving more timing.

humidity and atmospheric pressure affect performance as well as dino stated. but im not sure how

Bryan

<small>[ February 24, 2003, 04:15 PM: Message edited by: really slow truck ]</small>

 

yes, atmospheric press will affect how much air gets through the intake. if you live in higher elevations, like denver, the air is less dense due to lower air pressure. that is why homeruns in baseball travel faster when your team plays the colorado rockies. maybe i should golf there sometime too. our trucks probably would run worse (at same temp) in higher elevations. those close to sea level obviously will run better due to the dense air and high atmospheric pressure. as for humidity, humid air is less dense than arid (dry) air. sounds weird, but it's true. i knew my earth science and meteorology minor from college would be good for something. also, when you order trucks from the factory, the trucks that get shipped to colorado are different from the trucks that get shipped to florida due to the elevation and pressure differences. hope i'm right on all this, or i must have really sounded stupid <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" />