Bucking / Bogging / Stuttering at speed

[irowiki]

So we picked up the 83, got her running, and started home. After our first gas stop, we noticed random bucking/bogging/lurching/stuttering at high speed (65-70 MPH, around 3k RPM).

At first, it only did it once and would stop, randomly. Then all of a sudden it would just lose power, bog down, and start "bucking" for lack of a better term. Usually would stabilize by the time we hit 55 MPH. 5th or 4th made no difference.

Did I get a bad load of gas? Fuel filter? Distributor/spark plugs/wires?

We're stopped at a rest stop for sleep so I'll check this in a few hours!

[marlinh]

Check the fuel filter. Sounds like it could be plugged. Maybe moisture in the tank getting into the filter. Throw some gas line antifreeze into the tank. It can't hurt. If the tank is good it may be sludge in the float bowl.

Did this car sit around for a long time?

[Gottolovem]

I agree with Marlinh fuel?
Hopefully you can limp home a few months back i was dealing with the similar symptoms.
It ended up being The screen in the tank was full of crap from me blowing out the hard lines backwards the car had ben sitting a long time before hand and the hard lines completely blocked.
If it acts worse uphill or at higher speeds It's almost certainly fuel related.

Other than it bucking hows the car?

[irowiki]

Car sat for 4-5 years at best bet.

Did put some heet in at the last fillup when the issue started. Related?

Oddly after a five hour break the problem went away. Replaced fuel filter anyway. Old one was hooked up backwards. That can't have been good?

Will post more about car later.

[Gottolovem]

good luck fingers crossed

[Petros]

sounds like partially plugged fuel filter to me too. I always put in some carb cleaner additive in the tank on a car that has sat and I will be driving it, might clear any crud or moisture out of carb. fuel filter is easy enough, autozone has them, use the same year corolla one, larger, and cost half as much.

[xirdneh]

also check the inside the distributor cap
see if the two spring loaded contact pins are still moving right

[irowiki]

Fuel filter did not help, it started doing it all of a sudden again after replacing the fuel filter for about 15 minutes in rush hour bumper to bumper interstate traffic, and then stopped. (phew) By then we needed to fill up anyway, so maybe this tank will tell if it was gas or not. It has not done it after the last tank.

Been using Heet, and lucas cleaner so far. Might try some Marvel Mystery oil.

xirdneh, where are these pins?

[Petros]

I have never had good luck with Marvel Mystery oil, it was recommended for a noise hydraulic lifter in another car we owned. When I put it in the oil It made it worse, and it leaked and smoked more too. So I changed the oil and the problems went away. I can not see any benefit to add it to the fuel at all. I would not try it.

[Vienna]

She's still at it. If while she's doing it and we put put the clutch in, she bogs and dies. If started back up, she'll sputter and recover if you give her ample gas. Still need to check the distrubuter, we haven't had time to do that yet.

Just had a scare on the freeway thinking the engine was smoking hardcore but after puttering her to safety there's no more smokey smell so it must have been someone else driving by at the same time she was bucking.

[Vienna]

Only seems to do it at highway speed at greater than 60, usually near 3K rpm. cruising at lower speeds in town seems fine.

[Gottolovem]

My money is on fuel starvation

[Petros]

could be that CVBT or whatever (device on the right fender next to coolant recovery tank), it is supposed to lean the mixture at lower rpms by bleeding air under the carb, supposed to shut off above about 2100 rpm.

Other possibility there is large chunks of deposits in the float bowl that came loose and is now randomly plugging and unplugging the fuel jets in carb. I have had this before, not normal in a car with a fuel filter but sometimes there are build-up of deposits in carb, and they dry up and crack when the car sits without running for a long time. than when you put fuel in it and run it again they float free and cause trouble. It is not that common, but it does happen. Usually the fuel system cleaner will help if it is not too bad.

other possibility is marginal coil, causing miss fire perhaps. it seems fuel related but it is possible it is spark. hard to test if it is intermittent. If you brought your spare distributor it might be a good idea to swap it out when you have a chance. make sure you get the rotor aligned properly when you install the replacement distributor.

[Vienna]

Could it be the fuel pump?

[Gottolovem]

It's possible its the fuel pump but not likely.
I think petros is on the right track with crud in the carb
Or like in my case crud in tank the carb is more likley i created my own problems in the tank.
Are you close to home yet?