96 Eclipse RS 420a
A little while ago this started, when i hit about 4 - 4.5k rpm the rpms start jumping outrageously, it drops to 2k, then jumps to 7k then drops again etc.(it goes from 2k to 7k so fast i think i hurt my neck, i wish my car always accelerated that fast). as soon as i let off the gas it goes normal again until i get up to 4.5k again. First i changed the plugs, it worked for about a day then started again. I just barely changed the coil pack and the plug wires, it runs better but still freaks out at 4.5k. Please help has anyone heard of this before? I was going to check out the fuel filter and pump, but am not sure. Thanks

I could be wrong but I think its the map sensor, I thought the map sensor causes that 4.5K freakout, replace it and you should be good to go

1998 dodge avenger 4 cyl AT
Mods are:
Not enough

I had that problem and it turned out to be my crank sensor. I got so sick of it that i eventually just started flooring the accelerator all the time until it threw a CEL so I could finally figure out what was wrong. lol Make sure that your crank and cam sensors are plugged in securely and check all the wiring.

Jason
'11 Ford Mustang GT/CS
'11 Ford Mustang V6 6-Speed (SOLD)
'04 Nissan 350z Touring (SOLD)
'95 Turbo Eclipse GS (SOLD and will be missed)
'90 Talon TSi AWD (SOLD)

Jason
'11 Ford Mustang GT/CS
'11 Ford Mustang V6 6-Speed (SOLD)
'04 Nissan 350z Touring (SOLD)
'95 Turbo Eclipse GS (SOLD and will be missed)
'90 Talon TSi AWD (SOLD)

1992 Plymouth Laser
-Bone stock for now.

Mine was the cam angle sensor. I once told my girl that I had installed nitrous and she really believed me cause of that thing. Just make sure the plugs are on tight on oll the things we mentioned then see how it runs.

I am parting out my 95 RS!!!

http://forums.2gnt.com/dcboard.php?az=show_topic&forum=49&topic_id=3652&mode=full

mine kinda does the same thing
when i floor it
the rpms go from about 4k to 6-7k then back to 4500 or so then slowly climb back up

i have been told that it is probably the clutch
slipping
could that be your problem

of course my clutch is the originaly one with 70k miles and i am boosting 10psi when the rpms shoot up so in my case it just might be

1996 eclipse GS-T
1968 Ford Mustang
2004 Suzuki GSXR600
2006 Honda CBR1000RR
Decisions Decisions

i had the same problem last month. it started at 4500, but eventually started doing it at all rpm ranges. i changed the crank and cam sensors and the problem was fixed