93 Sc bucking at 60+ mph

9

93atlsc

Registered User
When I get on the gas at about 60+ mph my car bucks. I have recently tuned it, new cam sensor, dis fairly new, new idle control valve, fairly new coil pack, and new ACT sensor. No vacuum leaks. The check engine light is not on. I have a bad feeling it's in my transmission. Please help! Thanks!
 
Have you checked your fuel pressure? Plug wires? Plugs? Check and make sure they are on all the way. Weak coil pack? some things to check before assuming its the trans.
 
None2Slow said:
Have you checked your fuel pressure? Plug wires? Plugs? Check and make sure they are on all the way. Weak coil pack? some things to check before assuming its the trans.
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also check for leak in the ic pipes, vac leaks. check your tranny dip stick to see if there is any burnt looking fluid/metal chunks. im thinking more along a fuel problem and or vac/boost leak. gl
 
those grounds will kill electrical parts im believeing thats what just killed my dis on my black 90

i always run a ground from the battery to the transmission bellhousing bolt

3 grounds to keep in mind are the ground for the o2 sensors thats located in the engine harness behind the supercharger some where in the vacinity of the fuel pressure regulator, that needs to be in good condition and bolts to the firewall.

you'll need a good ground from the battery to chassis, i welded a 4gauge wire from my battery ground to the chassis right underneath the front climp by the back of the headlamp housing

and i run a ground from the battery to the block just like the stock configuration but with thicker 4 gauge wire.
 
I would pull codes first. The EEC-IV will log some codes for intermittent issues that will not throw a check engine light. i.e. CID Interrupted.
 
When I drove my 92 easy it was fine. Under boost it would miss, pop and run like crap. I found a plug wire that was broke at the plug. Fixed this, but still persisted. Put a fuel pressure gauge on and running it was fine, but when I shut the car off, pressure would drop to 0. Turned out to be a cracked fuel line at the fuel pump inside the tank.
 
It has a recent tune-up, something I've gotten good at on these cars. It was bucking before the tune-up and it's still bucking. I just checked the vacuum lines and they appear to be in good shape. Wondering if it's the DIS module. I bought it off this site, but it was used. Usually my tach drops when I have a bad DIS though. I'll check for codes next, although the check engine light is not on.
 
mass airflow sensor did that to me ,cleaned it up and worked like a charm.i changed every ignition related part till i finally figured it out.
 
93atlsc said:
It has a recent tune-up, something I've gotten good at on these cars. It was bucking before the tune-up and it's still bucking. I just checked the vacuum lines and they appear to be in good shape. Wondering if it's the DIS module. I bought it off this site, but it was used. Usually my tach drops when I have a bad DIS though. I'll check for codes next, although the check engine light is not on.
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Were the wires replaced or just the plugs ? I'm asking, because I've damaged the wires enough to cause bucking under boost, just by changing the plugs. They looked fine, but they wern't.

avid
 
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