I have an 86 V6 turbo 4 speed that took a lot to get running right, for a while. New fuel pump, injectors, all the usual sensors, etc. Now it basically dies when coasting then you hit the gas and it jumps back to life. It also sometimes bucks under acceleration, but once that goes away it will run like a bat out of h-e double. toothpicks. My guess is it's not getting gas for some reason. Fuel pressures were good last I checked but it's been a while..

[This message has been edited by countach711 (edited 12-02-2015).]

Just (educated) guesses... fuel pressure, TPS

Pull the VSS plug on the transmission, check the pins and clean it .....re-seat. It's a cheap fix that may do nothing, but I have seen them loose contact before.

Almost sounds backwards but..EGR?

Check idle air control. (And there's no VSS plug if it's a 4-speed.)
Oops. I was thinking about TCC.

[This message has been edited by TopNotch (edited 12-11-2015).]

I have a VSS on my 4 speed and the plug has lost contact on more than one occasion.
If the speedometer is working, clean the connector under the speedometer (in the instrument cluster wiring) which may have come loose or corroded. It relays the VSS speed info to the ECM. If the connection is bad the ECM won't know what speed the car's going.

------------------
My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual

quote Originally posted by TopNotch: Check idle air control. (And there's no VSS plug if it's a 4-speed.)

VSS is the Vehicle Speed Sensor - all transmissions have them.
TCC - Torque Converter Clutch lockup is what a manual won't have.

------------------
My World of Wheels Winners (Click on links below)

3.4L Supercharged 87 GT and Super Duty 4 Indy #163

all good suggestions, I'll try them out.

Hey, Fiero Sound!! does the VSS connection bad or maybe a bad VSS give a code or check engine light?
I've got a similar problem but the computer is saying Po300 , Makes sense though. The speedometer
is working but it may not be sending the signal to the ECM .

Thanks!
Doug

THANKS, GALLl757!! Good suggestion!

[This message has been edited by CarolinaRigman (edited 12-12-2015).]

finally had time and weather to get to this. First I re-seated the vss plug and it seemed okay. I then replaced the original, slightly hand-bored throttle body because the one on it was a loaner.and I need to return it. I also replaced the tach filter with Rodney's. I took it out for a drive and it didn't do it's stalling or hesitation thing! I will try some more since we are having great weather this week, but so far so good. So I think it may have been the tach filter. One wire had broken on the old one, is it possible it was sending bad signals or 'confusing' the ECU somehow?

yes.

bad tach filters do many odd things.

so it wasn't the tach filter, it returned. I did solve it however after following the advice of the guy on here that burns custom chips for folks (I forget his name). He recommended I remove the MSD box I have in there along with the Accel coil and going back to stock, problem solved!