Acceleration issues
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Joined: Jan 2025
Posts: 63
Likes: 8
From: Texas
Acceleration issues
I bought a 91 C4. On the test drive the car would not accelerate properly. The seller said this was a new issues that just started happening on this test drive. He said on his drive to show me the car it was running fine. I believe him, I don't think he is lying to me.
The symptoms: light pedal push car accelerates slightly. Heavy pedal push the cars RPMs surges. If I floor it the cars RPMs keep surging up and down. If I lightly keep pushing the pedal the car can get up to speeds of 80mph.
The seller thought it might be the throttle cable that connects the gas pedal to the the throttle body. The cable had a small amount of play. If I push the throttle with my hand the engine revs and sounds fine. The cable did not feel like it was binding at all. How much play is supposed to be in that cable? The bottom one on the moon shape of the throttle body.
Here is what was replaced recently by the seller: Starter Battery, Ground and power cables, Fuel pump, Fuel filter, Stock injectors, Spark plugs, Spark plug wires Distributor cap and rotor.
What do you think could be causing this?
The symptoms: light pedal push car accelerates slightly. Heavy pedal push the cars RPMs surges. If I floor it the cars RPMs keep surging up and down. If I lightly keep pushing the pedal the car can get up to speeds of 80mph.
The seller thought it might be the throttle cable that connects the gas pedal to the the throttle body. The cable had a small amount of play. If I push the throttle with my hand the engine revs and sounds fine. The cable did not feel like it was binding at all. How much play is supposed to be in that cable? The bottom one on the moon shape of the throttle body.
Here is what was replaced recently by the seller: Starter Battery, Ground and power cables, Fuel pump, Fuel filter, Stock injectors, Spark plugs, Spark plug wires Distributor cap and rotor.
What do you think could be causing this?
Melting Slicks
Joined: Jul 2005
Posts: 2,202
Likes: 302
Could be a number of things unfortunately...
What exact injectors did he get?
Could also be the pickup coil within the distributor (if that's never been replaced). That signals the ECM for spark and fueling.
Could also be a faulty sensor. Check engine light on? Wonder if there are any trouble codes being thrown.
Any differences in this behavior between cold and fully warmed up?
What exact injectors did he get?
Could also be the pickup coil within the distributor (if that's never been replaced). That signals the ECM for spark and fueling.
Could also be a faulty sensor. Check engine light on? Wonder if there are any trouble codes being thrown.
Any differences in this behavior between cold and fully warmed up?
Drifting
Joined: Sep 2022
Posts: 1,450
Likes: 380
From: Liberty, SC
2023 C4 of the Year Finalist - Unmodified
Im not pro, but could it be a slipping transmission? or a misadjusted TV cable?
I have an 88 manual, so i dunno how the TV ties in but I've seen a lot of folks talk about them on the autos - which I assume you have.
I have an 88 manual, so i dunno how the TV ties in but I've seen a lot of folks talk about them on the autos - which I assume you have.
Thread Starter
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Joined: Jan 2025
Posts: 63
Likes: 8
From: Texas
I am not sure what injector he replaced them with. Judging by his work he doesn't cheap out. No difference in cold or hot. If the TV cable is misadjusted will that affect the cable to the pedal?
