87 2.5 - suddenly, rough idle!

[AMCJeepMJ]

My 87 has started and ran like a top for the past 4 years.

 

This morning coming off a light it felt like it was bogging down and I had to feather the clutch to get it the revs up enough to smooth out and then it'd go. Every time the engine throttles down after a rev it will idle roughly and have no power- even after a shift that wasn't revved high. I had to limp it back home to park it. Now, idle is rough with both a cold and warm engine (tried it after being parked for 8 hours in 35 degree weather).

 

Recent work in the past month: new clutch, new drive belt, new headlights, new air filter.

 

Other misc info: no cat, new muffler less than a year ago, no blue/black/white exhaust, 4 speed, 170k.

 

Any ideas? Throw anything out there you may think it is. I already am going to change the plugs this weekend and put a new radiator and hoses in it too (but now this happened).

 

Really- any ideas?

[87Chief]

Could be a misfire... Just throwing it out there. lol

[JCole]

MAP Sensor??

[dasbulliwagen]

My 87 2.5 would run like crap like that quite a bit, I did all the stuff you mentioned with tune up, gutted cat, etc..... finally put a new O2 sensor in it and its been great ever since. I think it was like $42 from the dealer.... but that was a few years ago, and at my employee discount. Still shouldnt be much aftermarket. Good luck.

[AMCJeepMJ]

O2 sensor... hadn't thought of that. I'll go through the easy stuff Saturday and move on to the sensor if plugs and wires don't do the trick.

 

Stay tuned.

[AMCJeepMJ]

Put in Bosch platinum plugs and new wires from Napa on Friday evening. Runs now as smooth as a 24 year old Jeep is expected to run.

 

Old plugs were nasty and gapped to .055. Old wires were brittle. Both plugs and wires were probably a decade or more old.