Hello, my name is jordan and i'm new to this forum. I'm having trouble with my 2001 ranger 3.0 5speed 2x4 with 167k miles. It started idling rough a couple weeks ago so i cleaned the MAF, IAC, Throttle body, and replaced the TPS. Initually it seemed to run better and the check engine light went off (now back on), but it's still not running right. It has less of a rough idle now, but the RPM's are sluggish to come down while shifting and the RPM's rev up to about 1300-1500 when coming to a stop then back down to around 1000. I went and picked up a fuel filter and PCV valve, which i'm gonna replace next, and had them run a scan. It said my computer was still cycling, but it had a TPS error code and a misfire in cylinder 6. gonna change the spark plugs soon and possibly replace the IAC and/or EGR. Any suggestions on this?

 

Hi Jordan,

I wouldn't replace anything, sensors rarely fail/break, mechanical and electrical issues(wiring) are most common causes for CEL(check engine light).

If you don't have one get a $25 volt/ohm meter, it will save you hundreds in parts and time.

Pretty much every sensor can be tested with one of these, O2 sensor is the only exception and computer tests that one.

When you replaced the TPS did you check the voltage, these need to be adjusted when installing a new one?
It needs to be .7-.95volts when throttle is closed and above 4.5volts when throttle is open all the way.

Cleaning the MAF and IAC is always good to do, as is a new fuel filter and PCV valve.

Ford vacuum hoses in your generation were lasting about 10 years, they goofed on the rubber compound and it tended to crack.
Rough idle could be a leaking PCV valve hose, that was a common one to have problem, check the hose carefully.

Yes, if you have an EGR valve it may have some carbon build up inside so isn't closing all the way, this would cause a rough idle.

Look at each spark plug when you take it out or mark them so you can compare them side by side, spark plug tips can tell you alot about conditions inside that cylinder.



I run a can of Seafoam in my gas tank once a year, it keeps the injectors clean.

 

Hey Ron thanks for your helpful information. I haven't adjusted or tested my TPS since installing it. I do have a decent meter to test it, but should I use a t-pin or just try to get the leads into the connector? Also, I did run a can of sea foam through the tank and changed the air filter just prior to my idling issues. Not sure if the sea foam may of caused a vacuum leak or not? I will definitely check the TPS voltage first. So if my TPS needs adjusting, would this be something that I could do without an expensive tool and lack of much auto repair experience? Thanks for your time!

 

My TPS reading at closed throttle is .382 volts and 4.33 volts at wide open throttle. Im not sure if i rotated the TPS correctly upon installation. Can i adjust the TPS or should i remove it and then test it again?

 

You need to adjust it, it should rotate enough to get above .7v with throttle closed, but needs to be below .95v
Throttle wide open should then be above 4.6v.

On most throttle linkages there is also a screw, that looks similar to an idle screw, it is for adjusting TPS voltage and to set stall idle at about 500rpms

After adjusting it disconnect battery for 5 minutes to reset computer, this will make it relearn TPS voltages.

I use sewing pins to pierce wires to test while hooked up

 

I tried adjusting my TPS a few times and never could get the voltage above .5 volts at idle. My TPS has built in cylindrical tubes that the screws fit inside, should I get a metal drill bit and bore the tubes out so I have more wiggle room? I've heard that I shouldnt adjust my idle screw, but in my case should I?

 

Today I changed my IAC and disconnected my battery for ten minutes. When i turned my truck back on, it idled a bit over 1800 RPM and would jump up to around 3000 RPMs while coming to a stop and would remain 3000 until i put it back in gear and took off again.
I read the codes after the IAC install and it said the flow speed was too high and also my TPS voltage still too low, but there was another that said TPS sensor A voltage was high. I tested my TPS again earlier and it was about .47 volts, so I adjusted the TB screw to get it up to about .71 volts. I let it run for a while and the idle was still pretty high. Right now i have the TPS at about .51 volts, it seems like i will have to crank the screw so much to get the TPS voltage high enough that the TB butterfly will be open quite a bit. Did change my spark plugs, but havent gotten to my fuel filter and PCV valve replacement yet(still not sure if i've correctly located the PCV, underneath the tube coming out of the back of the intake driver side?)

Sorry so long just, want to give all info that may be relevant. The scan also said that I have a misfire in cylinders 4 & 6. I'm just not sure what exactly to do, any ideas would be greatly appreciated.

 

Also my engine does ping while going up a hill while on the insterstate, but I feel like it's done that since new. Vacuum leaks; water, propane, brake cleaner....? One more thing I thought of is my throttle seems to stick(closed) while driving and makes shifting and traffic conditions rough on the drive train.

 

update
took my truck to the shop about a month ago and had them do a diagnostic. I had low compression in a couple cylinders and they suggested a head job for around $1500. I thought about it and ended up finding a 2002 motor with less than 100k for about $1000. Pretty much just used the block and heads from the 02 and all of my 01 accessories.

The motor idles and runs very smooth, but the throttle isnt smooth when lighty accelerating or decelerating. It's kinda jumpy. I havent checked my TPS voltage yet and I havent drove the truck but about 50 miles since the motor swap. Should i just drive the truck longer and see if adjusts itself, or should i start looking at the TPS, MAF, injectors, etc?