help

[pbiggs]

i have read alot of these forums looking for answers and can't quite narrow it down.i have an 89 carb model runs mint,starts great,idles great,everything seems fine.i drive 1 hour to work every day,and both going to and from work,the same amount of time,about 45 minutes onto the ride it starts bucking and seems like its starving for fuel.i have checked all the obvious,filters, pumps ect.and it continues the rest of the way to work.after sitting all day it runs great all the way home until the last 10 minutes or so and starts doing it again.anyone???????

[batstiva]

Mine started doing that a couple of years ago, tho doesn't sound like as bad as yours. Mine was more like a series of hiccups. And mine would start it about 30 minutes of running. Changed the plugs, wires, cap, and rotor button and the problem was solved. Don't know when yours were changed last, but it's something to consider.

[pbiggs]

new plugs wires cap rotor fuel filter.trying coil next.but it runs great for almost an hour.does it at exactly the same time every time im in the car.to run that good for an hour then start seems weird,once it sits for a little its fine then sure enough 45 to 1 hour later same thing.im thinking not fuel issue after all but not positive.i have a few of the same symptoms as alot of others but nothing seems to work

[scottxd45]

I'm just taking a guess but maybe it's the O2 sensor. I think the ECM doesn't look at the sensor until it reaches a certain temp so maybe it is running good until the faulty O2 sensor sends a bad signal. It could be maybe reading rich so it's cutting the fuel or the other way around a flooding it out. Don't take my word for this but I would test the sensor at least.

[scitzz]

I'm just taking a guess but maybe it's the O2 sensor. I think the ECM doesn't look at the sensor until it reaches a certain temp so maybe it is running good until the faulty O2 sensor sends a bad signal. It could be maybe reading rich so it's cutting the fuel or the other way around a flooding it out. Don't take my word for this but I would test the sensor at least.

Do the 89's have a check engine light? If so, wouldn't the o2 sensor set the MIL?

[pbiggs]

im going to check the o2 thing,it sounds similar to others with distributor probs.but it seems like it should act up sooner than it does.

[packrat427]

Did you check the sock in the tank ?

Also a possibility that you have a coil breaking down after that amount of time , the O2 should been plenty hot many times in 45 min.

[pbiggs]

i did the tank thing,zip tyed the screen in the proper place,fuel system is good up to the carb,also spark plugs are very white all the time,which says lean ,and oil has very faint fuel smell but looks good,plug wash maybe???

[WmWatt]

Do you have a vacuum guage? If you plug it into a vacuum hose when the engine starts acting up it should indicate if it is an ignition problem. I think the guages cost about $15 at discount atuo parts stores.

[WmWatt]

Oh, yes. Another thing which can act up when it gets hot is the ignition control module inside the distributor. Expensive little item but thanfully they can be removed and tested for free at some auto parts stores.

[pbiggs]

yeah i have read alot about the ignition module,but you would think that after 45 minutes of steady driving 55-65 mph it would have built up enough heat to act up sooner.and i can almost time it perfectly every time,within a 1/4 mile