1994 Navajo really rough idle need help to get to work tomorrow afternoon

[powersmx5]

I have a 1994 Mazda Navajo with 175,000 miles. The car has been running flawlessly until tonight (45 degrees out in case temp plays an issue). During my drive home at stop lights the car would idle for 30 seconds and then begin to make a chugging noise that will get progressively louder and then make the car shake. Each time the car shakes I notice the voltage gauge jump toward a higher voltage and the car switches to a fast idle of 1000 rpm. The shaking gets worse and worse but I haven't let it go to see if it will stall as I wanted to get home. Once driving and the rpm's are up over idle speeds the car behaves perfectly normal. So each stoplight I hit or stop for traffic it would idle ok at first then start to shake.

What should I look out for?

Vacuum tree by the master cylinder on the firewall
clean battery connections
IAC
MAF

looking for any suggestions it is my only car and I need it to get to work tomorrow afternoon

 

[Fordmandan87]

check the iac and where r u from

 

[lofton316]

check coolant, check pcv valve

 

[powersmx5]

Ok I will check all the fluids levels, vacuum lines, pcv, and IAC. How do you check the IAC valve just clean it or do a voltage check? I will run a search for it. Thanks for the suggestions. I am from Boston, MA by the way.

 

[powersmx5]

Thanks everyone for the help. I found the problem on the main vacuum tree (Octopus) a line had come off and the car struggled to idle. I popped it back on and zipped tied the line to hold it for now. The rubber cap had become stretched over time. I wonder why it finally popped off?

 

[purple-x]

im having the same problem with my 94 explorer it runs flawless after replacing the dpfe sensor and two days later when i come to an idle in or out of gear it chugs, when its in gear it wants to almost lurch a little but when i hold the brakes and give it a lil gas its fine. . . is the vacuum tree the little canister on the backside driverside of the motor by the intake plenum?

 

[LXNavajo_94]

sounds like both of you have a bad transmission modulator have you noticed a unexplained loss of transmission fluid you know it drops about a quart with no visable leak? over time the fluid gets sucked into the hoses and causes them to expand wich in turn causes the hose to come off and cause idle problems and all kinds of unexplained problems

 

[purple-x]

would the tranny modulator cause it to shift a little off also and make it hesitate to engage when going in and out of gears, its an automatic

 

[bigge4685]

that is what A mod valve does very easy to replace this is a goo dpost on this site about that.

 

[purple-x]

whats the link