Quote:
Originally Posted by Birchhatchery
i have a hesitation in my 3.0 97 102 thousand miles. I've replaced plugs plug wires coil pack, idle air control sensor, mass air flow sensor, fuel filter fuel pump ascending unit. what happens is truck fires up runs fine idles fine goes down high way no miss but when I come up to a stop sign and idle their for a bit and I push on gas it hesitates bogs down then picks right back up and takes off like nothing happened no engine codes either! only thing I can think of is 2 things I need to clean my Intake or my coil pack I may try putting old one back on seeing if that takes it away?
|
Sorry it took so long to get to your question, I have been busy dealing with subscribed threads and have had a chance to look for unanswered questions.
Did the truck run good before all the work you did ?
Did you have any codes before the work started ?
Did any of the problems you once had change after the work for better or worse?
From your description I would start with a Fuel pressure test.
Test the pressure with the engine running then shut the truck off and let it sit for 1/2 hour and see if the pressure bleeds down.
Post your findings.
The other thing that may be a possibility is a slight worn spot on the Throttle position sensor.
I have found that a TPS will wear out the most from the idle position to part throttle, this wear can cause erratic voltage to the computer that happens fast enough that the computer does not notice it and will not trigger a code.
I used to have to have a very sensitive Lab Scope to detect this type of malfunction. ( I admit this is a rare problem as normally a TPS will fail bad enough to trigger a code )
Most of the time a test of the TPS using a Digital volt ohm meter will reveal a obviously bad TPS.
Your TPS should have three wires normally unless my memory fails me the center wire " may " be the wire that goes to the computer and should read with a DVOM about 1 volt with the key on and go up to around 5 volts as you depress the throttle.
The other option is your truck is running fine and your throttle cable may be stretched not allowing wide open throttle.
To check for this have someone hold the throttle to the floor with the engine off, look under the hood at the throttle body to see if you can manually open the throttle further.
If the throttle cable is the problem there should be plenty of threads on the throttle cable mod.
I looked everywhere for a new cable for my 2002 I had, and came up empty handed.
If you do a sweep of the TPS and find that it seems to function properly but will not go up to 5 volts this would be another reason to suspect the throttle cable.
Remember it could also just be a worn TPS if you are unsure ask questions and post your findings.
There are many other things you can check and other possibilities of what could be wrong but we have to start somewhere, getting feedback from you on the questions I asked is a good place to start.
The other information I provided may or may not be of any use depending on your answers. so do not rush out and buy or rent any diagnostic tools just yet.