Hey guys!

I have an issue that is getting worse and need a little help pinning down what may be going on. I will do my best to articulate what is going on but please feel free to ask some questions if I miss the mark. My fingers do not always get what my head wants out.

For a few months I have been experiencing some hesitation under load. By under load I am talking about cruising down the Hwy and when I go up a hill the truck acts like it is missing at 2300, 2400RPM rpm. If I step into the accelerator it quits and away we go. No power issues at any other time.

Now Thanksgiving day I went out to the garage to start the truck and the batteries were dead... Well almost. After recharging the batteries and testing them I figured out my alternator was the culprit. I replace the alternator tonight and returned my truck back to stock program and went for a test drive.

I putted around for a while and everything seemed to be fine. Once the truck was up to temp I started playing a little and when I went almost WOT the thing started acting like it was missing REAL bad and fell on its face. I repeated this several times and same thing each time.

I then plugged in the SCT and loaded the street tune that I have been running for the last year or so and tried the WOT test. Of course she took of like a rocket! However after trying to repeat the problem a few times it happened again and again.... I step on it... Spool up... takes off for a second and then acts like it is only running on 4 cylinders... Puke, buck, shake, and bang then away we go. Once the RPM's get up she runs out smooth... Its just under load that the problem happens again and again.

I have a few suspicions as to what could be going on based on all the knowledge I have gained from hanging around here...

1) FICM related issues. not firing the injectors correctly? Not my best guess because the truck starts and runs fine not under load.But with battery issues I thought MAYBE?

2) Sticking injectors

3) HPOP leaking rail?

If I am WAY off do mot hesitate to say... I am actually lost as to what to do to check any of these items out. Any and all help would be appreciated.

Thanks,

JT.

 

I should also mention that I have fuel PSI and exhaust temp gauges. Nothing abnormal there. Fuel stays between 66 and 70.

 

I had very similar issues. When its hesitating is it maintaing same gear and just using turbo to regain speed? That's when I noticed mine. Scanned it at local shop and came back as egr valve. Changed it with my buddys old one and it ran great again. I ended up just un plugging it a lil later and is still running great

 

Thanks for the quick response!!

My signature does not do a good job of telling this but the entire EGR system is gone! I am not getting any readable codes with my SCT either.... That is kinda weird to me also.

 

FICM is easy enough to check and it could be causing you issues. Since it's always happening at the same RPM I'd say HPO, tuning, or turbo issue, but check the FICM voltage first.

Does it do the same thing if you rollllllll into the throttle without kicking it down? Is it worse?

 

If I just rooooolllll into it it seems fine. But who drives like that? ;0)

 

Just an attempt at being funny...

I did not notice the bucking or hesitation when I was driving around normally. Just under load or when stomping on it from a slow speed or stop. Also as I said when cruising at hwy speed and increased load by going up a good incline.

 

Do you get any or a lot of black smoke (untuned) when this happens??

 

I cannot say for 100% sure as I was testing this evening after I installed the alternator and it was dark. I did see smoke one time when I was on the on ramp under a street light tho. But every time?? Not sure.

Why? Would that be an indicator?

And thanks partsman! you always come to the rescue when I have questions!

 

I'm thinking that it's an issue of the turbo not responding correctly. I would say HPO, but you've already done the STC fitting so I'm not going there yet. It's the "I step on it... Spool up... takes off for a second and then acts like it is only running on 4 cylinders... Puke, buck, shake, and bang then away we go. Once the RPM's get up she runs out smooth... Its just under load that the problem happens again and again part that says turbo to me, except for the "spool up" part.

 

That part has got me confused a bit also. I seem to have good boost pressure all the way through the studdering and missing.

I did replace the STC fitting but is also my understanding that you can get a high press oil leal on the -O- rings feeding the injectors???

Im getting close to throwing in the towel and taking it in

 

Check the FICM voltage, the fact that your batteries/alt. went dead may tell the tale as the FICM is very sensitive to proper battery/charging system maintenance.

 

I'd bet 'striction...... but then every time I bet on something, I'm wrong! LOL I too would also check the FICM voltage....I'd do that whether or not you check the injectors!

 

Well i threw in the towel and had my truck put on the scanner. I was at a point that I had a good suspicion but could not tell for sure and didn't want to replace parts for no reason.

I have 6 out of 8 cylinders missing due to the FICM...... The good news is I found a brand new ford FICM for 460.00 + 12.00 to ship it to me!!! WOO HOO. The local stealer quote me over 700.00!

Thanks for the input guys. i thought I would follow up with you to let you know what I found out.

 

Thanks for the report Jason. Strange that it's always happening at the same RPM's but nice to know for the info.