Stumble/Miss at 1500 rpm

Oceanside · 10-15-2011, 05:30 PM

I rebuilt the 7MGE in my 1989 Supra. .030 oversize pistons, new bearings, head rebuilt, new everything, MLS head gasket, ARP studs. Runs great, idles perfectly. However I get a stumble at 1500 or so RPM. Happens when I slowly rev in neutral or when I accelerate. Bad enough that the check engine light will flicker sometimes, but will not remain on, Will happen in all gears if I shift early enough to get the rpms to drop below 2k. If I punch it during an acceleration stumble, it will miss and stumble worse. It is driveable, but very annoying. Fuel pressure is fine. New distributor cap, rotor wires and plugs.

Did not do this prior to being rebuilt, not sure what has changed.

Oceanside · 10-16-2011, 02:38 AM

Spent the whole day looking for a vacuum leak, finally narrowed it down to a small exhaust leak by the 02 sensor.

10-15-2011, 05:30 PM	#1
Oceanside Stock Join Date: Oct 2010 Location: Oceanside Posts: 6	Stumble/Miss at 1500 rpm I rebuilt the 7MGE in my 1989 Supra. .030 oversize pistons, new bearings, head rebuilt, new everything, MLS head gasket, ARP studs. Runs great, idles perfectly. However I get a stumble at 1500 or so RPM. Happens when I slowly rev in neutral or when I accelerate. Bad enough that the check engine light will flicker sometimes, but will not remain on, Will happen in all gears if I shift early enough to get the rpms to drop below 2k. If I punch it during an acceleration stumble, it will miss and stumble worse. It is driveable, but very annoying. Fuel pressure is fine. New distributor cap, rotor wires and plugs. Did not do this prior to being rebuilt, not sure what has changed.

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10-16-2011, 02:38 AM	#2
Oceanside Stock Join Date: Oct 2010 Location: Oceanside Posts: 6	Spent the whole day looking for a vacuum leak, finally narrowed it down to a small exhaust leak by the 02 sensor.