I'm new to this website, I've seen forms and whatever on here but never made a account or ever thought I would have wanted to post. I've been having issues with the old 2002 ranger (3L), I thought the big issue was fixed a few months ago (the positive wire going from battery to fuse block was broken, at the splice for the battery and alternator) but today it happened twice when I was out on a job. Engine wouldn't go back to idle, under load (sitting in gear) about 1,000 rpm and no load of maybe 1,200 rpm. This is intermittent so bear with me, on the scanner it showed the computer wanted 700 rpm for the idle, I don't remember what the iac was doing but the spark advance was at 36.5° and I think before it went higher (I looked back and I've seen it at 40°) and that's not moving. Engine hot at about 192°F. And normally when its happy its usually at 12°. Next issue which is probably related is the engine when happy doesnt want to return all the way back down to idle when driving, 1,100 is about where it wants when it does fall but it's a little slow to come down and feels like in fighting the engine when I'm braking (almost like I still have my foot on the pedal). At work in the parking lot (maybe a small decline) the truck falls to 1,500 rpm and holds and will start to accelerate by it self. Higher speeds are better I think it's still a little slow but the truck immediately starts to decelerate. Is that normal? I don't have another ranger I drive to compare to and this is annoying when I'm trying to carefully move something. I noticed when I was trying to get more data when it freaks out that when it was happy if I let off, the iac goes to about 50% and spark advance goes to 25° and refuses to drop. And the iac does slowly go down. Any help would be appreciated, my uncle is a mechanic and he works on it but he thinks it's the trans and says to rebuilt it but the rpm slowly dropping happens in natural as well so I'm not sure if it's the trans. I'm thinking maybe the fuel injectors, I bought the truck 2 years ago and I haven't done them that was about 50,000 miles ago. I believe my uncle said one side was replaced but I have no clue when. Fuel trim sits at -5 I believe. Again any help would be appreciated, before I bought the scanner I did fire the parts cannon on cheaper stuff like coolant temp sensor, throttle position sensor, and I even tried 3 differant IACs. Could this be old fuel injectors or could the engine be out of time? Am I missing something? My uncle rebuilt the engine before I bought it, (original guy sold it to him, uncle fixed it up, then I stumbled upon it) i have a nicer scanner so I can see a lot of the data, so I can get other things if wanted. Oh and there is a small miss or at least it has a small shake at idle. Thank you and have a good day. If this is the wrong thread then sorry, I can always copy and paste it, I'm new so please bear with me.

 

Also what would cause the pcm to advance the spark so much? I tried looking it up but I haven't had any luck

 

start the motor, let it warm up. unplug the IAC and see what happens. it should almost die.

 

It does Edit: rpm drops and almost stalls

 

ok IAC is working, maybe take some screenshots of you fuel trims. let motor warm up to temp first. long term is what to look for. how many miles on the speedo?

 

I'm probably going to run out and get something later so I'll get the fuel trims later. The truck has 342,623 miles on it, still in good shape. 2nd engine with original trans. If memory servers me correct I think long term was at 0 and short was -5 or maybe it was the other way around. I ill post it later, I have a good 20 minute drive one way. Thank you for responding

 

if its that old, the O2 sensors should have been changed 3 or more times. im kinda thinking it a fuel issue. that could make the timing off. PCM trying to keep up to a fuel problem. the O2 sensors could do that if they aren't working right.

 

I went out, I got 3 different scans. 2 of them are just a few things mainly focusing on fuel and the last is all the data. thank you again

 

note page 5 bank 1 sensor 1 Lean. bank 2 sensor 1 Rich. but the numbers on LT fuel trim look OK? something is kinda off. maybe pull a plug one on each side to see what they look like

 

I've been doing premium fuel for the past 2 years, when I was on regular I would get some noise. My dad said it sounded like spark knock and to try a different fuel.

 

the is a screw adjustment on the IAC its not an idle adjustment sometimes people try and adjust it. check to see if its back it all the way off so theres some play in it. its for anti knocking or pinging

 

I don't have that. Here is a picture of a spark plug. I changed them a few months ago. oops wrong button, I added the iac too. Ugg I'm hitting all the wrong buttons sorry

 

I don't upload:/

 

is that 1 from each side?

 

no, when I changed them a fee months ago they all looked the same and like that spark plug. That's the front of the truck on the passenger side

 

ok thats bank 1 and the sensor says lean and it looks lean. pull one on the other side too. bank 2 that side said rich. we'll see if it looks the same as bank 1.

 

I took a screenshot of the o2 sensors voltage with the graph. That took a few minutes to find and transfer to my phone. And I'll take the plug out from the other side give me a minute

 

Driver side and front of the truck

 

same one this isn't allowing me to upload both pictures

 

the O2 sensors dont start working until the motor is warm

 

if thats both sides they look good. so any idea when the O2 sensors were changed?

 

That was warm, though it was sitting for a hour

 

its got to come up to temp 195dg

 

no idea, I can ask my uncle but I don't think he'll respond until Monday. I believe he does keep some kind of a list of what he did on the vehicles

 

I can go around the block and take another screenshot of them, if you want