Loosing Power at low RPM.

[Fanatic1074]

Hello all, i have been noticing that my truck has started to loose power at lower RPM's (1000-2000). Sometimes i will take off from a dead stop and just will have no power. Then it gets up to about 1800 rpm or so and starts to act normal. But it does not do this all the time.

Now about 6 months ago i did install a CAI and Flowmaster exhaust and also started using the superchips programmer but none of this power issue started happening until recently. I tried swapping tunes via the programmer also and nothing changed.

Anyone got any ideas?

 

[dcarr]

when was your last tune up. plugs, wires, coils, FUEL FILTER? also what year is your truck

 

[Fanatic1074]

changed plugs fuel filter about 30k miles ago.

Mine is a 2003 Expy XLT 4wd with the 5.4 motor.

Never have changed out the coils at all. But i would think if it was a coil that the engine would shake and it would throw a code. However its smooth acceleration.

 

[dcarr]

i lost couple coils in my 07 and they seem like they get weak before they die. 30k on the fuel filter with this new garbage fuel i would say start there. cheapest thing to try.

 

[Fanatic1074]

OK great ill check out the fuel filter.

Not sure how to check the coil packs. if i remember correctly you have to check resistance from the pack right? anyone know the proper way?

 

[Fanatic1074]

Ok, filter is fine.

However i have noticed something. I took the truck on a 900 mile round trip and it seemed that when the temp got higher i had more problems. I left around 12pm and all most the entire way there i was having power delivery issues. Downshifting not only into od but also down into 2nd.

Then on the way back i was loaded up. 12 ft trailer with my buddies stuff on it and the truck on the inside filled up as well. We left at 8pm and i think i only had one instance of the truck feeling like it was low on power.

Also i noticed that when it feels like its low on power its not just the low RPMs. Its just when it happened before i was only at low RPMs.

Anyone got any ideas? My best bet at this point is O2 sensors. What you think?

 

[Thermo]

Fanatic, it may be that you are having an issue with the air temp sensor. If that is reading high (caused by a high resistance in either the sensor or the associated wiring), the computer will see the air as being thin and it will reduce the amount of fuel going to the cylinders. But, once you get the RPMs up, the truck is moving and the under hood temp falls a little bit and clears up your problem.

 

[Fanatic1074]

Would this theory also hold true if i was maintaining 70 mph?

Just want to make sure before i start buy alot of new parts.