1988 7MGE Misfire - Stumped!

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Originally Posted by excaliburdj

Timing is set (per the manual) at 10 BTDC. I checked it when I first got the car back together, and then I checked it again after about 30 miles. Still right on.

Good, so that's out.

Originally Posted by excaliburdj

As for the vacuum leaks, any specific places you'd check?

If the hoses look remotely stock, I'd just replace them all... although this doesn't usually result in an intermittent problem.

Originally Posted by excaliburdj

The distributor is a $15.99 Autozone brand - nothing special.

The cap and rotor perhaps... but the distributor costs a bit more. There are sensors inside the distributor body which detect the cam position so the ECU knows when to signal the igniter. A short, an open (∞), or too much resistance on that specific harness can cause timing issues that you won't see at lower RPM.


Then I would move on to testing the AFM and TPS when they are warm. Test the resistance across E2 and VS on the VAF while moving the vane inside. Test across E2 and VTA on the TPS while moving the throttle plate. The resistance should change with little to no spikes or sudden drops. HINT: Using a hair dryer to make sure the component you are testing is good and hot may help identify a problem you would otherwise miss.

While you're testing the AFM, test the FC switch. when the vane is closed there should be ∞ between E1 and FC and when the vane is held open there should be very little to no resistance across E1 and FC. Also test the IDL switch in the TPS.

VAF info:
MK3 TSRM On-Line

TPS info:
MK3 TSRM On-Line