Hey everyone, this if my first post on this forum. I have a 1988 Ford ranger 4x4 2.9 V6 that I just bought from a buddy for $650. He recently put a new clutch in and 02 sensor. My problem is, when I start it it idles high and then drops to like 500 RPM's, then pulsates up and down from 500 to 1000, lights flickering and then it eventually dies. I checked the vac lines and they seemed fine, battery is good. Also when I do get it going and press the gas after shifting gears it pauses for a second, almost like it is going to stall but it doesn't.

I'm hoping this isn't a major problem because I really like the truck, but I'm not going to put a ton of money into a $650 truck. It starts up everytime btw, just dies after some rough up and down idling. If you need more info let me know, otherwise thanks in advance for the help, I didn't know where else to go.

HERE IS A VID OF IT: http://s806.photobucket.com/albums/y...0102011121.mp4

 

ok list of easy checks and fixes:
1. clean Mass Air Flow sensor in intake.
2. is the fuel filter any good? if its stock on a 98 then youve got a problem, easy fix though
3. if it has a idle throttle screw, screw it in till it presses the throttle body open a little more than normal just to attempt to regulate idle.
4. this is the expensive one. fuel pump, if it has gone bad your not recieve nearly enough fuel ergo...
oh and seafoam, it fixes everything but really it does

 

Pull off the IAC (idle air control) and clean it. its a common problem with the 2.9

looks like this

 

Thanks for the replies. I cleaned it and its still doing it. Its a 88 not 98, I had one of my buddies look at it and he cant figure it out either. It does this sometimes, but other times it runs normal. Any more ideas? I checked the IAC with my buddy and he said its fine, we adjusted the throttle screw. When the car is pulsating the lights dim with it. Any other help?? I appreciate it.

 

The weirdness continues. I just took it for a drive. The check engine light only comes on now when I am accelerating and it was idling at 2300 RPM's. Seems like it could be a sensor or something, any ideas?

 

this vehicle is older so my knowledge is limited however do you have a throttle body position sensor? if so i would inspect that to the best of your abilities. i.e. diagnostic at auto z if you even have to onboard ECU. otherwise it could be tons of issues: clogged fuel filter, broken fuel pump/sender, miss firing cylinder, improper ignition sequence, bad/dirty MAF, maybe the new O2 sensor got damaged on install (would double check).

the lights are dimming because as your truck climbs and descends through RPM's the belt is also speeding up and slowing down ergo alternator is getting a proper then low then proper charge i.e. light abnormalities.

with an idle that high it sounds as iff your truck is not reading the incoming air properly and therefore dumping fuel into the engine to compensate for unknown amount of oxygen. so double check MAF and O2

 

My 89 Ranger (2.9) has ALWAYS had that weird hesitation in the pedal right after you first apply the gas. From the day I bought it..



GB :)

 

Thanks for the info man, Ill check them out today in the 10 degree weather ...... I am not very mechanically inclined but I do my own brakes and some electrical ****. I like to mess with stuff and learn that way. I hope its not then end of this truck cause its a badass looking truck and when its running its still very powerful. Which is surprising to me cause I had a 99 ranger that was slow as hell. But then again, that was a 4 cylinder so I didn't expect much. Loved that truck though, got me 26 MPG in the city, got rid of it when it had only 50000 miles on it. Anyways, back on topic, ill check that out today and give you guys an update.

 

Where is Toledo? I live in Mundelein, ever heard of it?

 

Fire the truck up, when it starts running odd unplug the IAC. If it starts running smoother, thats what it is. Other than that its either a computer issue (ground or whatever) or the throttle body needs a severe cleanout. My bet's on the IAC though, they're a very common issue with the 2.9Ls.

There's no MAF on the 2.9Ls but they do have an electronic throttle body. It might possibly be an issue with the sensor in the throttle body as well so try unplugging it as well when its running. You won't harm anything by unplugging the sensors, worse case is it might stall and you restart the truck. Do it one by one to eliminate any variables. LR

 

Thanks man, I appreciate it. Its getting worse it seems. It dies right after I start it now. Used to take 20 seconds, now its like 3. I'll mess around with some stuff, I'm hoping its not the end of the truck :(

 

its your IAC, mine even does that when my IAC is dirty, when you pulled it off to check it, did you clean it? take some parts and brake cleaner and spray the crap out of it, then take a tiny screwdriver, and push the spring to open up the valve and spray some more, do it about every 7-8 months.

 

I cleaned the IAC yesterday with carb cleaner, its a newer part also.

 

theres one more plug type thing im thinking of, i just can't remember it for the life of me, its not far from your IAC, but cleaning it helps a ton too. it is defiantly some kind of idle problem.

 

I'm thinking ill just throw a grenade under the hood and see if it helps

 

Here is a video of it, it wasn't too bad this time, but I had to rev it to start it up. It died after 20 seconds. Click the link to photobucket: 0102011121.mp4 video by pacmanj4 - Photobucket

 

I'm a downstater man. Glad too! I couldn't take living up there in **** territory.. lol



GB :)

 

Ok I figured out why it was dying, my mechanic put a plug on the engine where he thought the line was leaking (one of those little suction holes). I took it out and it didnt die anymore, the only thing left is the RPM's still pulsate from 800-1300. Is it a big deal or should I just let it be since its not dying? Or whats an easy fix?

 

im still convinced the IAC is either dirty still or needs replacing.

 

I cleaned it really good and it looks spotless. The air filter is a k&n, but its duct taped on.. Looks like this one Amazon.com: K&N RF-1020 Universal Air Filter: Automotive. Idk if that is messing up the air flow or what, the IAC was replaced last year.

 

Glad to hear the truck is fixed! your vacuum line? I would put all my money to say that your RPM changes are due to the air intake system. whether it be this or that I would start at square one (the filter) and clean up to (and into) the throttle body. check to see if all wire connections are not corroded and making good connections and its easy and a can of air intake cleaner from CRC is 4 bucks. does it pulsate at lights...or only on cold starts in the morning? once again...seafoam (s**t's Jesus in a bottle)

 

Kinda hard to tell from the short vid but that might be a fuel delivery issue as well. Might need a fuel filter or the vacuum control for the fuel pressure issue (can't remember what the part's called). LR

 

I've never heard of seafoam. What is it and how do you use it? I'm going to take a pic of under the hood to show you how it is. It pulsates all the time, at lights and on cold starts. Man though, that motor is still strong as ****. I beat the hell outta it.

 

Here are some pics of the air filter

http://s806.photobucket.com/albums/yy348/pacmanj4/

How can I make pics show up in the post?

 

I tried some of that seafoam stuff. It seems to have fixed the pulsating idle. That stuff is cool, smoked like a mother ****er after the restart. The idle is at 1400 rpm's but steady. That one hole on the top of the engine where there used to be a plug (vaccum hole, can feel the suction) is weird. Its a small hole, maybe a little bigger than a bb, when I cover it with my finger it goes way low on RPM's and pulsates. If I cover half of it, it goes to lower RPM's with no pulsating. If I uncover it all the way it goes up to a steady 1400 RPM's. What can I do about that hole? Like I said I think it went to the air filter before it got switched out maybe?? I don't mind if it has a high idle, but if I can fix it easily then I will. Thanks for recommending the seafoam.