98 w/2.5 running rough and bouncing idle after tuneup
 

98 ranger reg cab stepside, 2.5L 4cyl 5spd 2wd

My ranger seemed a little low on power lately so I decided to give her a small tuneup. After I got into it I noticed that one of the dpfe lines to the egr tube was broken off. I drilled it out and set it back into place with steel stick. I then seafoamed the truck. I ran it for twenty minutes after I seafoamed and it ran better but still not perfect. . So I then changed the plugs and wires. I had to take the tb off to get the back two on the drivers side. I did my best to clean it. Get it all back together and when I start it the truck runs very rough. The idle eventually gets into a bouncing up and down rythm after 30 seconds or so. Any throttle at all and it runs fine and feels great. Only at idle is it causing problems.

I checked all the plugs and wires and they seem fine. Plus I think running well at throttle rules them out?

I am leaning towards iac or dpfe from what I learned through searching.

However nothing comes up for bouncing or surgeing idle. Its a pretty specific problem and I was hoping someone on here had any history or info on it. Any help would be appreciated.

sure you have your firing order right?

[QUOTE=djfllmn;1995732]sure you have your firing order right?[/QUOT

checked, checked, and triple3 checked

Clean or replace the IAC (idle air control) module. It is cheap and easy to change out. That is the problem.

just put a brand new one on. no difference.

so new plugs/wires
new iac
cleaned maf and throttle body

like i said the truck ran fine before the tuneup, not perfect, but ok. Now it is missing like a mofo.

I am going to go through the plugs and wires one more time.

I'm having the exact same problem with my 99 Ford Ranger. 2.5, manual. What ended up being the problem? And it solution

That was 10 years ago, but if I remember it was the dpfe sensor. One of the hoses was cracked and fell off. Grabbed a used sensor at a junkyard and the hoses. I also redit the egr tube at the same time. One of those fixed it. Pretty sure it was dpfe

I had a similar issue just the last couple of weeks. I ended up grabbing a loaner tool from AutoZone to check the fuel pressure. The fuel pump ended up being bad and not giving any pressure on prime. This caused my engine to run rough and was most notable on cold starts. I would suggest checking your fuel pressure and also seeing about using a timing light to see if perhaps one of your sparks is out of time. Just some helpful diagnostic tools I found helpful.