mickey5

my 1990 with 6speed runs great for half an hour then idles very rough before it dies. If left for an hour or more it starts and runs normally for another half hour before it starts all over again. During rough idle it won't throttle up past an idle. Squirting starter fluid into the plenum during rough idle lets in run smoothly. Fuel pressure and spark check out fine. Tech 2 diagnostics at chevy showed stored code 51 no pulse and 13 02 sensor.

TWISTERUP

I'm seeing code 51 as a faulty or incorrect mem-cal (e- prom)

tehcarguy

Check the O2 first, that a bit cheaper than a new prom.

jimmers

What is he fuel pressure?

Louis J Hoppmann

my 90 did the same thing take a screwdriver and tap on the emc my car would come and go after it warmed up replaced emc all ok

mickey5

pressure is 40 lbs. Pulled pump and rubber tubing did not show any deterioration.

mickey5

I'll have to get the code rechecked. How long does it stay in the ECM?