hammeron

did you ever raise your idle rpms? if not, you might try setting
drive idle rpms to 1000 and nuetral idle rpms also to 1000. it
might make the car less annoying, while you troubleshoot for
the real issue.

simplexdesign

I doubt bumping the idle up would help because most of the time its too high already. Plus I dont want to try to patch the issue I would rather it get worse until the problem becomes more obvious.

hammeron

yeah i understand.

well ham is on the job now, so we'll get this bugger fixed come he11
or high water.

Simon1

So here is my thoughts Ham.

If the fuel trims are okay, which seem like they probably are since the OP has not talked about a lean or rich condition in the CELs, then I would have to guess it may be in the dashpot. The dashpot controls either throttle plate or fuel/air input per gear. I recall when I my car was getting tuned earlier this year I had a surging while decelerating in gear and an hunting idle.

The tuner changed the values within the dashpot and the issue is almost completly gone. 2nd and 3rd gear could use some slight adjustment but it's okay.

I doubt it's a MAF issue since they seem to just completly die instead of work intermitantly.

O2 sesnor would throw those codes per bank, most likely.

The strange thing is with a stock tune and intake it does it? Is there a ghost in the software?

hammeron

i like your thoughts on the subject simon1. the stock tune with stock airbox, coupled
with surging rpms while the car is sitting still...is very interesting.

i've got to go back over this thread and outline what has and hasn't been tried, then
try to lay out a troubleshooting sequence.

MyLocalDJ

Hammeron... been a while dude. Hope you have been doing good.

Anyway, in reading through all of this, it reminded me of something strange that happened to me last winter which might help in the overall thought process. As stated, I have had this problem for a very long time and just learned how to deal with it. However, back over last winter, I had my battery die. When I replaced it and even reflashed the tune, there was something wrong with the tune. I even flashed multiple times. But the result was that my idle for both neutral and in gear were at about 1000 - 1100 and I had no idle surging or hunting issues. It was as if the aftermarket tune was not registering. My speedometer was also off and the tune was not recognizing the change in tire size. After about a month of riding around like that I disconnected the battery, uploaded the stock tune and then the aftermarket tune and everything was back to as it should be... including the idle surge and hunting issue! Just food for thought in this analysis.

hammeron

it has been awhile, doing good and good to see you visiting the board again.

i like these kinds of problems because they force us to learn about the way things
ought to be, in order to figure out what is going wrong. in this case, we need to learn how the pcm controls idle in a normally operating vehicle. for me, that's the next step.

hammeron

here's a review of simplex's comments over the last 10 months, so we can see
what's been done to date:



02-01-2010
It usually happens when I am slowing down and I put the car in neutral the rpms
will go down and then start jumping around under and over 1k without applying
the gas pedal at all.



02-05-2010
Cleaned my MAF sensor(Wasnt very dirty), took out battery, re-installed tune and
I am still having the problem.



03-23-1010
At this point I have Cleaned the MAF Sensor, Cleaned the Throttle Body, Changed
the Spark Plugs, Changed the Fuel Filter, Took out Battery and Re-Installed my
Brenspeed 93 tune



03-24-2010
Cleaned Air Filter, All bolts are tight, The Throttle body got completely taken
off and cleaned.



04-20-2010
They came back with a low voltage on the TB so they recommended to replace it.
Obviously I wasnt going to pay their $500+ to install one so I ordered a new take
off TB from Brenspeed installed it and I am still having the problem.



04-20-2010
The few Vacuum lines have been checked.



05-28-2010
I went to ford earlier this week and had them reflash the pcm and I reinstalled
my factory airbox and sure enough it seems like the problem is gone.



06-19-2010
As of right now I have only driven the car maybe 100 miles and I honestly think
that ford reflashing the pcm masked the problem and the computer is just
correcting/adapting to it.



07-17-2010
Problem is back and it is factory tuned with factory airbox back on so I am really
lost to what the problem is.



11-29-2010
the rpm jumps at a stand still without any movement.






MODS: The only real motor mod is a tune and intake by brenspeed running a 91 octane
tune with exhaust work.

simplexdesign

Damn hammeron thanks for laying that all out like you did I appreciate the attention to the thread. I just realized this problem is coming up on a year of existing which is entirely to long.

hammeron

you are welcome and we're all happy to help get this sorted out. i think
simon1 is on the right track with thinking about dashpot function. i've started
looking at the service manual for clues and also my advantage III help files, which
explain quite well how idle is managed. i just have to let it sink in for awhile
before i can make heads or tails of it.