93 Dakota idles rough
Registered User
Joined: Sep 2013
Posts: 6
Likes: 0
That could honestly be anything. Step one is always do a good tune-up. Include the following:
-Fuel filter
-Spark plugs
-Plug wires
-Cap-n-rotor
-Air filter
-PCV valve
Once those things are done, mount a fuel pressure guage to the fuel rail (located driver's side, about 2/3 back to firewall). Check what your pressure is when idling. Ideally, 30-40 psi is in the ballpark.
Next, grab an automotive stethoscope and listen to each fuel injector while the engine is running. You should here a clicking pattern. The pattern is sort of important, but not at this stage of the game. What is more important is that all of the clicks sound like the same pattern. If one of those things is not like the others, you may have a fouled injector.
Has your computer thrown a code? There is a technique listed here on the forum (I remember reading it, but can't remember where), that talks about a series of ignition key turns which will cause the ECM to dump codes. I don't know what it is, but I have an Innova 3120 that pulls all the codes and then uploads them to my PC for evaluation. You might be able to get one on loan from the parts store. If not, shell out the couple hundred dollars. It's worth every penny in time savings. Anyhow, if it threw a code, fix that problem that threw the code.
I replace a bunch of crap recently, mostly because when I solve a problem, it stays solved. That said, I changed out the IAC motor and some other crap... I listed it all in another post.
If none of that fixes it, you'll actually have to do some real troubleshooting. Everything I listed (except replacing an ECM) is normal maintenance items that need to be addressed on an interval, whether that interval is 3k miles or 100k miles.
-Fuel filter
-Spark plugs
-Plug wires
-Cap-n-rotor
-Air filter
-PCV valve
Once those things are done, mount a fuel pressure guage to the fuel rail (located driver's side, about 2/3 back to firewall). Check what your pressure is when idling. Ideally, 30-40 psi is in the ballpark.
Next, grab an automotive stethoscope and listen to each fuel injector while the engine is running. You should here a clicking pattern. The pattern is sort of important, but not at this stage of the game. What is more important is that all of the clicks sound like the same pattern. If one of those things is not like the others, you may have a fouled injector.
Has your computer thrown a code? There is a technique listed here on the forum (I remember reading it, but can't remember where), that talks about a series of ignition key turns which will cause the ECM to dump codes. I don't know what it is, but I have an Innova 3120 that pulls all the codes and then uploads them to my PC for evaluation. You might be able to get one on loan from the parts store. If not, shell out the couple hundred dollars. It's worth every penny in time savings. Anyhow, if it threw a code, fix that problem that threw the code.
I replace a bunch of crap recently, mostly because when I solve a problem, it stays solved. That said, I changed out the IAC motor and some other crap... I listed it all in another post.
If none of that fixes it, you'll actually have to do some real troubleshooting. Everything I listed (except replacing an ECM) is normal maintenance items that need to be addressed on an interval, whether that interval is 3k miles or 100k miles.
Has your computer thrown a code? There is a technique listed here on the forum (I remember reading it, but can't remember where), that talks about a series of ignition key turns which will cause the ECM to dump codes. I don't know what it is, but I have an Innova 3120 that pulls all the codes and then uploads them to my PC for evaluation. You might be able to get one on loan from the parts store. If not, shell out the couple hundred dollars. It's worth every penny in time savings. Anyhow, if it threw a code, fix that problem that threw the code.
Registered User
Joined: Sep 2013
Posts: 17
Likes: 0
CEL up on the dash? If no, start with a solid tune up. Fuel filter, Plugs, Wires, Cap, Rotor, Air filter, Oil change, 02 sensor, make sure your pcv isn't plugged. Grab some injector cleaner (I like Seafoam) and run in through your gas. As a side note, when I did my massive tune up about a week ago I noticed that my Ignition coil had a massive crack in the case, and was filled with corrosion. The truck ran fine IMO, but was wayyyy better after I replaced it/did my tune up.
Cheers, Spinner
Cheers, Spinner