Hello,

I have a 1992 3.9 Auto 2WD Dakota and Im having some strange issues...

It started one day when it was running in the parking lot and it was idling funny... it'd jump from 500 RPM to about 1000RPM with no one touching the gas... Then on the way home the truck just went dead as I pulled into the driveway.

Ok, I had a mechanic look and he replaced the heat sensor (never heard of one of those anyways)... Well, it's still idling the same and when you romp the gas while idling it makes a loud "SUCK" noise... And there is a LOUD sucking noise coming from the intake while idling.. it starts off quiet and gets louder until the point where people around me walk away scared that its going to blow. It's a loud hissing or sucking noise.. It's hard to describe.

Along with those symptoms, it's known to just go dead at time (maybe that's fixed not sure since mechanic worked on it) and when starting out it wont go very fast at ALL... im talking over 5MPH... It's really annoying and confusing! I'm thinking about running some seafoam through it and seeing what that does....

OH, someone put RUBBING ALCHOL in my gas tank because they though I had water in it... That may be the cause of some symptoms but all of them??? Just tell me what you guys think!

Thanks,
-Jason

 

rubbing alcohol is the same thing as heet, icopropal alcohol which is made to get moisture out of your gas tank and lines, so that would not have an affect on your idling speed. for that i would check your mass airflow sensor and air filter. if your filter looks clean the pick up tube might be blocked so try running it with no filter at all for a few seconds and see if that cleans up the idle. go with the easy cheap things first, if that's not the problem then check to see if your choke is stuck open, if you have throttle body injection, if it is then thats why its running ****ty. i hope that helps, if it doesnt i'm sorry but that all i can think of.

 

Well, I dont have a Mass Airflow Sensor... I have checked and it idles bad with the filter and everything off... im not sure about the rest... Do 1992 Daks even have a choke? Ah well, thank you for your reply! I will check it out! THANKS!

-Jason

 

I had problem on an s-10 years ago that was pretty close. The rpms would surge, which is usally a sign of a bad Trottle Position Sensor (TPS) but that did not fix it. I had to clean and eventally replace the air idle valve on the side of the throttle body. May not work but its worth a try.

 

When I first bought my '94 with a 3.9 throttle body, it wouldn't stay running. It was the idle sensor, so that could be what's making it run rough.

 

I have the same problem. I just got a cotization from a local autozone dealer, a new IAC, for around 650 pesos (58 dllrs). A friend of mine gave me one from an old spirit crysler. I just havent had time to swap it and make some tests.