Hey guys, I feel like I have become a regular on here now after only having the car for 2 weeks but it is what it is. So I was driving my 1988 fiero formula (has a 3.1 roller cam block with bigger injectors and a bigger TB and an egr delete--idk if it matters or not) last night, pulled into my neighborhood and stopped at a stop sign. I put it in first to pull away and boom, it starts bucking, engine light turns on, car is essentially controlling itself. I would push the gas and it would cut in and out and in and out. The bucking was pretty bad, totally undrivable like that. So I pulled over, shut the car off, started it and it was back to normal....and I was hoping that was it.... So I get home from work today, go to take it out, I made it a few miles down the road, I stop at a stop sign and put it in first gear, it happens again, same thing, very bad bucking, I managed to make it off the road (barely). I did the same thing, turn it off, wait a few then turn it back on, and everything is fine. (Engine light is back off) I don't think it has to do with the clutch or anything transmission wise because it goes into first, then when I try to press the gas, that's when it happens. It is almost as if someone is giving it 1/4 throttle, and letting off, over and over again. Engine braking, and then accelerating. It's bad I do not enjoy it haha. You guys have any idea on what this could be? I have absolutely no clue and don't even know where to start. Extremely Thankful for any help or insight! I just want this fixed!
Without going through the entire diagnostic list, you should start by checking the obvious items; vacuum leaks, loose wires/ grounds. If this doesn't turn up anything, then you'll need to start confirming individual systems; fuel, spark/ electrical, air, etc.
...do you guys know if that would turn my CEL on? Because when this symptom happens, it turns on for the duration of it,. If I turn the car off and back on again, it runs fine and normal. But the CEL is OFF again, so I don't think I can even read what the code WAS saying.
I need to buy a code reader, im going to do that after work today and check and see what it was. Also another idea I had was the TPS sensor? Could that be linked? It seems like it doesn't know where the throttle is suppose to be and then tries to do something- that's not pleasurable to experience.
In my experience bucking = EGR problems. Do you have an EGR?
I do not have an egr and it's not tuned, yes I know it bucks pretty good going under 25 because of the egr, (I just ordered a new chip should be here later this week) but that is not causing this, this seems unrelated from the egr. It never did it before, then 2 consecutive drives it did it, after it was running fine for 30 minute's each time, hence why I'm so confused, makes me lean forward something electrical.
Can't be that. When I say "bucking" it's more as the car takes full control over the gas pedal and pulls itself ,then stops, then pulls, then stops, etc etc.. Motor mounts would be all the time too, I would imagine, this only has happened 2 times, although I have not driven it since the second time because It can't happen on the main road...(yea it already did...that was NOT a fun experience let me tell ya)
This is the high-priced piece of hardware (with minor modification) that I use to read codes.
I had to skip 2 days meals and got one for each of my 2 cars. I love them because they are so compact that I can keep them in the door pocket or the dash pocket. The batteries seem to last forever, too.
Ben2002, since you're somewhat new here, you may not know of the New England Fiero Association (NEFA). Contact Ray Paulk, president at 88GT@FieroPride.com I think he's up in the Lowell, Mass. area, but they have members through all NE states.
Remove the trim plate over the cigarette lighter. On the passenger side, inside the opening you will see the diagnostic terminal. Fold the paper cllip into a U shape and insert the ends into the two lower right terminals. Do this with the ignition off. Also turn the ignition off before removing it.
Once it's inserted into the two terminals, turn the ignition to the RUN position. The Check Engine Soon light will begin to blink 1 time then 2 times. This is code 12 meaning the system is working. It will flash a 12 for a total of 3 times. Then if there are any trouble codes stored, it will flash them 3 times, for example 3 flashes, then 2 flashes = code 32, meaning EGR system fault. Once all trouble codes have been displayed, the system will start again with 12 and repeat all codes 3 times until the ignition is turned off and the jumper paper clip is removed.
The trouble codes are listed at the left of the Pennock's home page, telling you what each number combination identifies. Once you have all the codes written down and identified, you can clear the codes by disconnecting the round connector coming from the terminal box at the battery. Leave it disconnected for about 30 seconds then reconnect it.
Make the repairs identified by the code(s) then restart and drive the car at road speeds for about 10 minutes. The car won't perform well initially until the computer relearns all of its sensors and their input values. If the Check Engine Soon light comes on again, you haven't repaired the issue. Repeat the above procedures.
Remove the trim plate over the cigarette lighter. On the passenger side, inside the opening you will see the diagnostic terminal. Fold the paper cllip into a U shape and insert the ends into the two lower right terminals. Do this with the ignition off. Also turn the ignition off before removing it.
Once it's inserted into the two terminals, turn the ignition to the RUN position. The Check Engine Soon light will begin to blink 1 time then 2 times. This is code 12 meaning the system is working. It will flash a 12 for a total of 3 times. Then if there are any trouble codes stored, it will flash them 3 times, for example 3 flashes, then 2 flashes = code 32, meaning EGR system fault. Once all trouble codes have been displayed, the system will start again with 12 and repeat all codes 3 times until the ignition is turned off and the jumper paper clip is removed.
The trouble codes are listed at the left of the Pennock's home page, telling you what each number combination identifies. Once you have all the codes written down and identified, you can clear the codes by disconnecting the round connector coming from the terminal box at the battery. Leave it disconnected for about 30 seconds then reconnect it.
Make the repairs identified by the code(s) then restart and drive the car at road speeds for about 10 minutes. The car won't perform well initially until the computer relearns all of its sensors and their input values. If the Check Engine Soon light comes on again, you haven't repaired the issue. Repeat the above procedures.
This reminds me... Do you maybe have a battery disconnect switch?
[This message has been edited by cebix (edited 04-24-2021).]
No. I don't see any need for a battery disconnect switch unless there's battery drain and you have an unrepaired problem like fuel pump continues to run, headlight motors continue to run or click, or the like. If it's to create an anti-theft method, unplugging power to the ECM would have the same effect. Just remember that any time power is disconnected, the ECM has to relearn after the car is driven some distance at operating temps and road speeds.
If this is in regards to disconnecting power to the ECM to clear codes, the easy way is as I described. Just unplug the barrel connector that usually hangs in the area just below the positive battery terminal.
No. I don't see any need for a battery disconnect switch unless there's battery drain and you have an unrepaired problem like fuel pump continues to run, headlight motors continue to run or click, or the like. If it's to create an anti-theft method, unplugging power to the ECM would have the same effect. Just remember that any time power is disconnected, the ECM has to relearn after the car is driven some distance at operating temps and road speeds.
If this is in regards to disconnecting power to the ECM to clear codes, the easy way is as I described. Just unplug the barrel connector that usually hangs in the area just below the positive battery terminal.
What I had in mind that maybe the author was using a disconnect switch everytime he drove. So that would mean every drive was a re-learning procedure for the ECM which might to some extent explain bucking.
EDIT: Oh I see I quoted your post but meant to reply to the topic author.
[This message has been edited by cebix (edited 04-24-2021).]
So I have an update, I ran the codes, it had code 34 - map sensor. I got a new one, I also was doing the slave at the same time and my clutch line decided to start leaking fluid when I was bleeding it so I ordered a new one from the fiero store, so I can't test it until I get that installed...just my luck. Does anyone have any idea if that could've caused my issues? A faulty map sensor? Seems odd to me.
In my experience this code points to a vacuum leak, not the sensor itself.
I hope your wrong and I didn't just waste 60$ but it I had a vaccine leak wouldn't the light be on all the time? It was only on during the time when the car would drive itself. Then it would go back off when I restarted the car
I hope your wrong and I didn't just waste 60$ but it I had a vaccine leak wouldn't the light be on all the time? It was only on during the time when the car would drive itself. Then it would go back off when I restarted the car
You know, this is just my experience, we'll se how it goes for you. Those sensors rarely go wrong - it's either their wiring or the vacuum hose that goes out.
