I have a 02 lev ranger with 2.3l and when i start it up the thing revs to
2500 rpm then drops to about 750 rpm after 3to5 min.
what will cause this please help if you can.
The surging problem i have is after you drive 5 to 10 miles the truck will
start to surge and loose power.
I have replaced the iak that did not help
I do not have any codes coming up i had the dealer do a scan and they sad
there are no codes present, $80.00 wasted and no help from them if it does not tell them what is wrong they have no clue.
can anyone point me in the right direction to solve this problem i am having.

 

Sounds like the IAC (or is that the iak you mentioned?) -- the IAC is the idle air control solenoid. It's adjusted with a pulse width modulated signal to control the idle.

Either the PCM or the IAC could be having a problem. OR, the MAF perhaps. Intermittent failures of the MAF don't get detected and reported very well. On my '02 3.0 liter I can disconnect the MAF and the first code I get, and only after a couple of minutes, is that the intake air temperature sensor reports bad and not the MAF.

Without a code, it's tough sometimes. Have you reset the PCM? Disconnect your battery for 15 to 20 minutes. Now reconnect it and start the vehicle and let it idle for 15 minutes without driving it. This will force the PCM to relearn the idle air control strategy and though I don't think it'll solve the problem, maybe it'll help.

Any pinging or knocking when it surges?

 

I was having a bad stumble off idle that is y i replaced the iak, the other
problems i am having just started the other day out of the blue.
There is no knocking or pinging when this happens it just just revs when i start it and looses power after 5 to 10 miles like when every thing comes
up to temp.Ihave tried switching out the iak agian that did nothing for
for problems i am having know.
I have cleaned the maf and it was dirty fibers from air filter stuck to it, that did not help. I just ordered a manual to see if it will helpme get this thing right.
If and when i get the manual i hope it will tell me what ohm all the sensors should be then i can start checking every thing to see what the problem is.

 

What is the IAK??? I don't recognize that acronym.

The MAF is not a simple ohmic sensor. You won't be able to easily test it. The IAT sensor (intake air temperature sensor) is resistive and easy to test.

Oil on the MAF, or a dirty IAC passage, could account for it. Sometimes, oil on MAF's gets burned on to them by the self-cleaning heating instead of being burned off and permanently alters the calibration -- or so I'm told. I know oil effects them but I've never actually seen one destoyed.

 

iDLE AIR CONTROL IAC just a little frustrated with my truck did not check spelling. I cleaned the MAF with electronic cleaner it did not help.
I will reset the PCM tomarrow and see if it helps.
I have also changed plugs ,wires, fuel filter and air filter .

 

I went back to the dealer on sat. and they gave me credit for the work they
did becuse the truck still has the same problems .
I reset the PCM this did not help.
The dealer said it could be coolant temp sensor going bad but they will not
switch out parts tring to fix a problem, They do not have a clue what is wrong.
No codes they say the truck is runnig correctly.
I drove all over yesterday to see what would happen and what I have came up with is that it is a heat soak issue now i just have to find the problem.

thanks for the help