2.5L ('98-'01) Need help diagnosing surging/rough idle issue.

[Brain75]

so your 4 cyl engine has a tach off a .... 4cyl? 6 cyl? (most common/most likely) - almost guaranteed it is off if that is the case.
From your video it sounds like a vac leak to me, but not as consistently surging as I expect with a normal single small vac leak.
No codes have come back in all the time you've been chasing after clearing?
Did you write down the original codes?

 

[saminator0107]

so your 4 cyl engine has a tach off a .... 4cyl? 6 cyl? (most common/most likely) - almost guaranteed it is off if that is the case.
From your video it sounds like a vac leak to me, but not as consistently surging as I expect with a normal single small vac leak.
No codes have come back in all the time you've been chasing after clearing?
Did you write down the original codes?

Im not sure if it is off a 4 cyl or 6. And no i didnt think to write down the codes. They also have not came back since i have cleared them, which i feel is odd since its still running weird.

 

[saminator0107]

so your 4 cyl engine has a tach off a .... 4cyl? 6 cyl? (most common/most likely) - almost guaranteed it is off if that is the case.
From your video it sounds like a vac leak to me, but not as consistently surging as I expect with a normal single small vac leak.
No codes have come back in all the time you've been chasing after clearing?
Did you write down the original codes?

Also i may add, i pulled the breather hose that goes from the valve cover to the TB and turned myself into the smoke machine with my vape.... lol. I did not see any smoke come out of anywhere else in the engine bay besides out of the air inlet for the intake. I did it while the truck was off and held the TB wide open while i blew on it.

 

[saminator0107]

Also i may add, i pulled the breather hose that goes from the valve cover to the TB and turned myself into the smoke machine with my vape.... lol. I did not see any smoke come out of anywhere else in the engine bay besides out of the air inlet for the intake. I did it while the truck was off and held the TB wide open while i blew on it.

EDIT: Disregard these next few videos. Read my post below. I had an idiot moment... haha!


Well now it has decided its time to start stalling at idle, this is a SEMI-warm start. Just scanned for codes, none present. I also looked to see if the TB was dirty, it looked okay.

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[saminator0107]

Well now it has decided its time to start stalling at idle, this is a SEMI-warm start. Just scanned for codes, none present. I also looked to see if the TB was dirty, it looked okay.

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I took some more videos. Im starting to wonder if this is a fuel pressure problem. The truck seems to want to stay running, but cant for some reason.

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[saminator0107]

I took some more videos. Im starting to wonder if this is a fuel pressure problem. The truck seems to want to stay running, but cant for some reason.

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Nevermind, disregard those videos. Just realized i forgot to plug in the MAF when i checked to see if it was dirty. LOL

 

[saminator0107]

Nevermind, disregard those videos. Just realized i forgot to plug in the MAF when i checked to see if it was dirty. LOL

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This is the holding RPMS i was talking about. It now runs perfectly fine besides this. I finally was able to get a video during the day. I obviously dont want to keep driving it like this as it will probably wear out the clutch quicker because the only way the rpms go down is if i engage the next gear which forces the rpms to drop.

 

[Brain75]

I don't see cruise buttons on the wheel.... does it have anything to do with cruise control under the hood, 2nd throttle cable, servo, etc?
I would tend to look directly at a sticky throttle cable first but when I first put in my dealer add on cruise control and didn't have the clutch pedal all linked up correctly I got similar behavior for a short time (it bumped up 100 rpm, but then returned after 1/2 second).
If you wind it up to 2k/3k at park and let off does it have any sticky spots coming back down?

 

[saminator0107]

I don't see cruise buttons on the wheel.... does it have anything to do with cruise control under the hood, 2nd throttle cable, servo, etc?
I would tend to look directly at a sticky throttle cable first but when I first put in my dealer add on cruise control and didn't have the clutch pedal all linked up correctly I got similar behavior for a short time (it bumped up 100 rpm, but then returned after 1/2 second).
If you wind it up to 2k/3k at park and let off does it have any sticky spots coming back down?

Yes this truck does not have cruise control. And the gas pedal feels fine, no sticky spots or anything.

I have found another thread that describes the same problem i am having.

Engine RPM's won't decrease when clutch is disengaged

I have a 1998 Ford Ranger 3.0L XLT 4x4 the engine RPM's won't decrease when clutch is disengaged. For example if I shift from 2nd to 3rd @ 2500rpm's, I lift my foot completely off the gas and disengage the clutch (depress it) the engine rpm's will maintain 2500rpm's as long as I keep the clutch...

www.therangerstation.com

I looked at the TB and it did not look dirty. Previous owner said he got the TB cleaned by christian brothers automotive. I might try to clean the TB again and see what happens. Starting to think the TPS might be reading off.

 

[Brain75]

If you tap the throttle while in neutral and "stuck' does it ramp up and drop back down?

checking the TPS

 

[saminator0107]

If you tap the throttle while in neutral and "stuck' does it ramp up and drop back down?

checking the TPS

Sorry for late response. I dont have a multimeter on hand but im headed to my buddies place later today and he has a fancy snap on scanner that i can use to see some live data. He also has a multimeter so we can test the TPS. No, tapping the throttle while not moving doesnt present any issues of being sticky. Thats one of the first things ive checked. I also tapped on the TPS sensor with the handle of my ratchet while the truck was running to see if it would act up, and it never ran weird.


Also another question. I have considered doing an EGR delete on this truck after hearing the valves like to get carbon on them pretty bad. My question is how hard would it be to do? Im in an area where there arent any state inspections (safety or emissions) so i dont have to worry about an emissions test.

 

[saminator0107]

Yes this truck does not have cruise control. And the gas pedal feels fine, no sticky spots or anything.

I have found another thread that describes the same problem i am having.

Engine RPM's won't decrease when clutch is disengaged

I have a 1998 Ford Ranger 3.0L XLT 4x4 the engine RPM's won't decrease when clutch is disengaged. For example if I shift from 2nd to 3rd @ 2500rpm's, I lift my foot completely off the gas and disengage the clutch (depress it) the engine rpm's will maintain 2500rpm's as long as I keep the clutch...

www.therangerstation.com

I looked at the TB and it did not look dirty. Previous owner said he got the TB cleaned by christian brothers automotive. I might try to clean the TB again and see what happens. Starting to think the TPS might be reading off.

So my buddy and i scanned the truck. It has no CEL or anything. The only code that came up that was drivability related was a vehicle speed sensor fault.

We drove the truck around and looked at the live data and it all seemed fine, even the vehicle speed seemed accurate to what the cluster was reading.

I wonder of the trucks uses vehicle speed to help determine fuel? That would make complete sense. Its just odd that theres no CEL and the speedo still works, because typically when a speed sensor fails the CEL is on and the speedo stops working.

 

[SenorNoob]

I just did a quick look and P0500 seems to usually be ABS sensor related not necessarily the same sensor that is used for the speedometer.