Bucking and high RPM

[N3FOL]

I have a 95 SHO ATX. Lately, everytime I am on the highway my SHO would buck and then the RPM jumps up all the way to 3000 and sometimes up to 6000 RPM on the highway. It gets pretty scary, since I will tend to slow down right away with other cars behind me travelling at 65 mph. I do not get any CEL, but it has been happening more often. What seems to be the problem?

 

[Black '93]

If it is just jumping up to 6000 RPM that is most likely a transmission issue. I assume it is not gaining speed when this happens right? If the cars RPMs jump like that without the throttle sticking and the car gaining speed, then your tranny may be popping into nuetral as your driving. Your foot is on the gas in order to keep the car moving at good speed on the highway, but if it slips out of gear it will rev much higher. That would also be the reason for no CEL. Tranny problems rarely give a CEL. It could be a faulty shift solenoid or the bands could be worn out and they slip out of gear when there is too much power going to the wheels.

 

[N3FOL]

Transmission Problem

Black'93,

I really hope that I am not having any transmission problems at this point. It has been two change oils and I neglected to check my transmission fluid level. My mistake...the transmission issue is what I suspected, but it is the last thing I want to think about. So far, my 95 ATX has 158,000 miles on the original transmission. Thanks for your input.

 

[Mr95Gl]

Just another suggestion. Check your battery connections. I had a loose terminal that would cause the car to downshift from 4th, to 3rd, then onto 2nd. Also, next time it happens, glance over at the EATC. If all the characters are lit up, best believe it's a lose connection/bad ground some where. Have you had any trouble started the car?

 

[N3FOL]

Starting

Just another suggestion. Check your battery connections. I had a loose terminal that would cause the car to downshift from 4th, to 3rd, then onto 2nd. Also, next time it happens, glance over at the EATC. If all the characters are lit up, best believe it's a lose connection/bad ground some where. Have you had any trouble started the car?

Mr95GI,
I never have trouble starting the car lately. But there was a time when I was starting the car and turned the ignition, my radiator fan came on and it wouldn't start. After a few try and the radiator fan turned off by itself (wierd), the car fired right up. It is just not normal for my fan to turn on, because the engine is still cold. (just my observation) As for battery connection, it looks good. For grounding, what specific ground in the car should I check?

 

[Mr95Gl]

There's a ground wire that runs from the negative battery cable, on to the passenger side strut housing IIRC. As for your Rad Fan turning on before starting the engine, no idea. Maybe someone else can chime in on that situation.