Hey all.. so on my 1997 f150 5.4l v8 i have the idle issues where if i let the truck sit running it rpm jumps up and down a little bit. Also when i first start the truck its a little ruff for example: If I am parked in the garage facing the open door and i start it the first time. IF i am facing inside the garage where this is some air restiction it stalls the 1st attempt but starts right up the second time. Also notice that if i hammer the gas pedal right after i start it up and hesitates. If i let it warm about for about 30 second or more she runs like a normal truck should i guess. Truck runs good under normal driving conditions and conditions where i feel i need to race someone. I did put is Granentelli MAF last year to go with my AF1 intake and every since its been settin goff my p0171 & p0172 codes for lower bank co2 sensors on both sides and i have to reset it every couple days. What do you guys think? Is my Co2 sensors causing all the problems or could it be something else?

 

If im not mistaken p0171 is lean bank 1 and p0172 is rich bank 1.

 

Yep, that sounds right!

 

Try putting the stock MAF back on and see what happens.

Phil

 

i will try that.. and report back!!

 

Quit resetting those codes and FIX the thing!

 

I agree. Granatelli MAF is the problem. When the engine is cold it starts out in OPEN LOOP. That means the PCM is using tables to control the engine. The O2 sensors are ignored. Your MAF is too wide so too much air is flowing through it. The Tables in the PCM have not been adjusted for the increased air flow. Granatelli uses a sensor that modifies the signal that goes to the PCM. The PCM then adjusts according to the modified signal. At low speeds the MAF is less able to compensate for the lower air flow.

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You should let it warm up for a while before hammering on the throttle period.

 

ok.. so I put my stock MAF back on and no issues with the engine light coming on, i check for codes anyways and nothing. I still have issues with "first start idle" kinda rough but then good after 30 seconds or so. Ran it 2 days stock, then cleaned and re-oiled my AF1, unhooked the battery for 1 hour and put on the Granatelli MAF. Then Put back on the battery. Ran for a day then the the engine like came back on for the same codes. Come to find out the MAF was calibrated for 5.4l v8 with no cold air intake and can not be reprogrammed. I am going to keep it for now, what a differnce in Power i get with it. When i was stock MAF for 2 days it sucked. Guess I will deal with engine light and it still passed inspection. I would like to figure that rough first start issue without paying the big bucks.

 

Sell the Granatelli and get a custom tune.

Regards

Jean Marc Chartier

 

#1 you may have damaged something running a MAF you're not tuned for, you do not "calibrate" a MAF for your truck, you have the tune adjusted


you need a custom tune and probably a spark plug change at the bare minimum

it's your truck and if you damage something because you want that's on you butn I don't want to see a thread about how your truck blew up because you ignored the check engine light due to your laziness/lack of caring to get a custom tune for the "performance" part you installed

 

thanks for the tip tarajerame.. I do not want to damage my truck but I am looking for an excuse to put a Super Snake crate engine in it. I am not worried about spark plug wires cause i don't have any and the plugs are new. Anyone want to buy a MAF for a 5.4l v8 1997 that works with stock intake?

 

Check for vacuum leaks. Possible cracked or broken PCV hoses/elbows/tubes?