stutters badly over 3,000 rpm

[Red_Rider_00]

'01 3.0 with K&N fipk cold air intake, jet module, poweraide throttle body spacer, cat-back straight pipe(no muffler). Engine bogs down under hard xceleration or even when overdrive downshifts in high gear. Basically, over 3,000 rpm it seems to miss, although new plugs & wires & coil pack & oxygen sensors. Trans not slipping because rpms go down when stuttering instead of going up. A mechanic friend thought it was clogged injectors so I added 2 pts of 91% alcohol to a full tank of 93 octane fuel with absolutely no change other than truck ran like a scalded dog but continued to miss the same. Code reader shows no new trouble codes. I don't think it's a major problem, however it just aggravates the heck out of me. Please any suggestions greatly appreciated and will be immediately tried. Thanx

 

[almostclueless]

What brand of plugs? Please dont say bosch...

 

[Red_Rider_00]

how did u know?

Believe it or not, plugs are Bosch platinum 2 which have two tips and are fairly expensive so I just figured they would be good. What plugs do you recomend and I will go immediatly and change them. Thanks so much

 

[almostclueless]

A lot of people have posted around the net that bosch plugs with the fine center electrodes end up discovering that center electrode either FALLS OUT IN THE CYLINDER or burns away, creating misfires. There are many threads here with boscdh misfire reports.


I am sold on the motorcraft dual platinums specified for the engine/vehicle in question.

 

[Red_Rider_00]

motorcraft it is then

Going to get them now thanx again

 

[Red_Rider_00]

No. New mototcraft plugs and still have the same problem

 

[almostclueless]

If it were my truck, I'd be heading straight to the local ford dealership and plunk down 60 bones for a good diagnostic. It's a lot cheaper than hoping the next parts fix it in most cases.

 

[Red_Rider_00]

nogotofomoco

I'm a firm believer that I can fix anything on my truck myself. Actually, other than exhaust and tire mount & bal, nobody but me has touched it. But, anyway, it doesn't really act like a miss but, more like an occasional stutter. Very violent under full accelleration. Maybe 3,200 rpm it like, shuts down for 1 or 2 seconds then picks up then bogs down again. Aaaaargh!!!

 

[Hahnsb2]

Clean your MAF. K&Ns and MAFs don't play nice with each other.

 

[Red_Rider_00]

not MAF

Thanx for trying Hahns, but I cleaned MAF with CRC and still stuttering.

 

[Viva*the*Ranger]

Did this start after a mod or out of the blue? I know you said you cleaned your maf, but at one point I had a similar problem and replacing the maf fixed it. And I cleaned it as well as I could before hand.

 

[fastpakr]

Is your CEL on?

 

[Accord4tehloss!]

Check the fuel pressure under load driving were it starts studdering you may have a partialy clogged fuel filter bad regulator or weak pump.

 

[WNY964x4]

Clean your MAF. K&Ns and MAFs don't play nice with each other.

Thanx for trying Hahns, but I cleaned MAF with CRC and still stuttering.

i hate to undermine anyone on this site , especially hahns , but cleaing the MAF prolly was not such a good idea , i have heard both sides of this argument , since i was a boces student for auto tech , and i worked at a parts store , i am a firm believer that it does more harm than good , but on to your problem

it was deffinently not the maf since a bad maf would cause it not to run at all

how long have you had the k&n on the truck and what kind of driving conditions ? i only ask because as of this week i am driving my stepdads F-150 and he has the same setup , it was doing the same thing , under acceleration and when the trans downshifted to climb hills , around 3000 rpms it would start stuttering , well his filter had been on there 8 years and 70k miles and never been cleaned , i used the recharge kit and the truck stopped stuttering.

if the cel is on have it scanned , if it is not , check your air filter to see how dirty it is , and i agree with accord , check the fuel filter , since neither of these will throw a dtc

 

[Earl43P]

Sounds as if the PCM doesn't know it's in Drive.

Transmission Range Sensor?