Surging?

[o. l. t.]

When my 4.4 is cold I have a surging issue when just starting out each day. I have to pull out of the garage and go up a small hill and it lunges like you are tapping the throttle as I am going up the hill holding the accelerator steady at just enough to make the truck move forward up the hill. Really touchy surging throttle. Only below 1/5th throttle. Once I get out on the street and go I don't see the issue. Just pulling through the driveway or a parking lot when it has started for the first time that day.

The issue is much less noticeable when it has been driven that day, though it occasionally does do it when warm so I am not sure it is a heat/cold issue.
It is not throwing any codes and is spectacular other than that.

I was wondering if anyone else's truck did this?

[Big "J"]

First thought is Idle air control valve or MAF sensor is dirty or going bad.

See what others may suggest?

Good Luck!

[Isambard]

I have had that exact same issue for a bout 2 years now! The only responses posted have been 'tranny software issues', and 'maf sensor' bad as Big J has said.

I replaced the MAF sensor but still it persisted. I haven't done the software upgrade-1. Because it will cost £££'s as mine is an '01 with no warranty, 2. Because so many people have said it has made no difference, and there never seems to be a conclusion by anyone to say it fixed the problem, therefore it couldn't have been the root cause. 3. I don't believe its to do with my tranny as its as smooth as a baby's arse-damn near as good as a Merc!

So, thanks Big J I will look at the air idle control valve, that one hasn't come up before. (any pointers as to where it is?)

o.l.t, even though I share your experience I have put up with it for 2 years now (had the car 3yrs), I just put my foot down enough to get rid of the surging but not too much that I'm driving hard from cold-I'm sure you know what I mean. I hope you get it sorted, and thanks for bringing this up again, I'll have a look at the air idle valve and report back my findings.

Good luck with yours!

[Weasel]

I haven't personally came across this issue to diagnose in the shop, so I couldn't begin to accurately guess... Does it seem to be engine or transmission related? (RPM surge or only physical movement surge)

[Isambard]

Physical-small jerky movements. Nothing major, but definitely noticeable and not right. For me (I'm pretty sure o.l.t is talking about the same thing) its always from a cold start, it doesn't matter on the outside temp-winter or summer-its just when the car is started from cold (left overnight etc..).

Again, for me, it lasts about 200-300 yards then it clears. Mine is a 4.4 also.

Weasel, can you tell me whereabouts the air control valve is, what it looks like, and perhaps an indication of what I might find that is an obvious fault? Or indeed something else to be looking at that you think could play a part? Thanks for your input.

[o. l. t.]

Yep as most state it is just jerky tapping of the throttle and then loss and then back on and off like tap dancing on the throttle for the first few hundred yards when the truck is undriven that day. If I were to record it on video it would look like I was just popping the gas pedal randomly and the truck jumping. It's a throttle surge and it acts like you are tapping the connection of a battery to an electric motor like little shockwaves of throttle surge.

[MiCkEy]

disconnect the MAf at the start of the day and see if that makes a difference.

[Weasel]

The V8's in these don't have separate idle control valves, it is a function of the throttle control. The reason I was asking if it seemed to be in the engine or transmission is I have seen the torque converter lockup clutch circuit fault out in the valve-body/mechatronics and pulse the lockup clutch every second or two when at a steady cruise around 40-50 mph... but this doesn't sound like that issue.

[RPM IM M]

Hi
I have an 2001-4.4 and it does just what ur saying
as well. Even when hot. I can see the rpm gauge fluctuate somewhat. It surges even in 4th before final gear and torque converter lock up
Quite annoying and I would like to fix it , but have been driving with the surge for 8 months as well

[huntertec]

I have a 3.0d not a 4.4 however I had similar issues and it was the EGR valve that was faulty, may not be any help but never know.