Trying to diagnose a problem...

[pontiacgp]

you should also check to see if the EGR valve is sticking....as for the distributor the only obvious problems you'll see is a broken wire or a stuck advance. The rest is electronic so unless you have the equipment to test it your only option is to switch out parts, one at a time..

 

[Derision]

So... er... the problem seems to have stopped. Which kind of worries me, because I never managed to track down what it was in the first place.

I did get a new distributor, but I have yet to put it in. Also replaced the alternator, as that was making noise... that made a world of difference (I can actually turn my rear defoggers on without the lights dimming!), but the issue had already fixed itself by the time I did that.

EGR valve, good. PCV valve, good. I'm going to do the plugs and wires and whatnot anyway, because it's been about six months since I last changed them, but I'd still like to have known, for sure, what it was that was causing it.

Ah well.

 

[LemansWagon]

The TPS sensor on these carbs (I assume it is an electronic q-jet) can often cause this kind of problem if it is out of adjustment or bad.

 

[ryanwitski]

I had the same motor with the same problem in an old camaro. Honestly it would come and go. They suck to work on. I just gave up and went to old non CCC and got a new dizzy and stripped all the crap. ran better. ofcourse that is a hack fix. If you have no egr function then, thus your heads will get tons of carbon build up in a couple of years.

 

[Derision]

The TPS sensor on these carbs (I assume it is an electronic q-jet) can often cause this kind of problem if it is out of adjustment or bad.

Yeah, it's just the regular old stock Quadrajet. Where's the TPS sensor located? I'll give it a check next time I'm under there.

I had the same motor with the same problem in an old camaro. Honestly it would come and go. They suck to work on. I just gave up and went to old non CCC and got a new dizzy and stripped all the crap. ran better. ofcourse that is a hack fix. If you have no egr function then, thus your heads will get tons of carbon build up in a couple of years.

I want to try to leave as much of it there as I can. I'm thinking about pulling of several of the exhaust components (my exhaust has been vibrating a bit so I think it might be time to redo it), but most of the actual engine stuff I want to leave on.

 

[gbody5]

Take the Cap off and check your rotor, make sure it has not come loose. I have had this happen on occasion, it will cause the ticking sound like you sometimes hear and can come and go as it sometimes "rights" itself and makes good contact. If distrubtor is old it could also have some play in the shaft/bushing but that is usually constant and won't fix itself.

 

[85 Cutlass Brougham]

The TPS sensor is located inside the carb on the driver's side. It has a 3 wire plug running out of the front and is either a white or black plastic socket. There is an adjustment screw on the top of the carb that is right around the accelerator pump lever and I believe it is adjusted with an Allen wrench. However, my memory may be wrong and it could actually need to be set using a specialty tool designed just for this purpose.

 

[shotgun]

My 83 Wagon was doing something very similar.

I paid close attention to how and when it would act up.

It was when cold and worse when wet out.

Found the wires to the temp sensor in the thermostat housing were loosing thier casing,about 1/2 inches of bare/corroded wires in the cover.

One of the guys had a harness from his SS,so I spliced the new end on from his harness.

Also replaced the sensor with his,since mine was the "early" design and his was the better "later" design. They also have different plugs.

Any way,95% of the start and rough idle have cleared up.

My quess is between the exposed wires and the old sensor,it was telling the car it was much colder than it really was. The carb was rich,loading up at idle.

At the very least pull yours out and hit it with a wire wheel to clean her up.

You never now,I it will take about 2 minutes to do.Have something handy to plug the hole or drain a little coolant first.

I still have some more diagnosing to do,but the lions share is fixed.