Dholla

So recently I have experienced power loss, weird shifting patterns, idle fluctuations that make it drop from 800rpm to about 400 and back and forth almost stalling at some points. I just replaced the IAC yesterday as well and it's still doing this...

Any idea of what could be wrong? My truck has 122,000 miles on it...

I was thinking maybe a vacuum leak or bad spark plugs?

MyFX4Project

Whens the last time you had your plugs changed? Can you hear any vacuum leaks around the engine? Whens the last time some maintenance was done like MAF, throttle body cleaning, fuel filter? Exhaust leaks can rob power too.

Dholla

the plugs have never been changed as far as i know and what noise do I look for when looking for a vacuum leak?

Dholla

Bump*

Warhammer

I know it sounds too simple, but have you checked your battery and battery cables? The cables can be corroded up inside the insulation without obvious damage on the outside.

droptopfox

im going to be "that" guy, do a full tune up then come back, fuel filter clean maf and tb plugs wires air filter clean battery terminals,at 122 its over do for a good tune up,maybe i missed it but what is the truck motor tranny combo? year? also check for codes

Dholla

Yeah I completely agree... it's a 2001 5.4L 4x4. I think this is what I'm going to do though. Hopefully it won't be too hard to do most of this. I recently bought a Haynes manual for the truck so looks like I will be using that a lot in the future.

The battery looks good from the outside and was recently cleaned up

How do I check for codes though??

Dholla

So I just got new plugs, throttle body cleaned, maf cleaned, iac replaced, fuel filter replaced and fuel injector cleaner put in and my truck still feels like it has power loss.

Im really confused and any suggestions in where to go from here?

DrillRig52

To check for codes take it to an autozone and they will do it for free.

The next thing I would replace is the COPs, or the coil over the plugs. When they wear out it can cause rough idle, misfire, poor mileage and acceleration. I've heard good things about Accel replacements. I found them for 175 with free shipping for all 8 at racemart.com.

Either that, or bite the bullet and pay a dealer 100 bucks to figure out exactly what it is so your not throwing money at things that aren't broke. Good luck bud

Dholla

I did not know that AutoZone could do that. I def will take it there than and have the coils checked. Thanks for the help!