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91 Sub - surges & dies at idle

I'm back again to see if anyone has any new ideas. Took it in to a shop this time. They said the manifold gasket was leaking so that got fixed. So far, have replaced the plugs, plug wires, cap & rotor, EGR valve, TPS, idle air control valve, timing chain and gears.

Idles somewhat bette after the manifold gasket but it still dies. Idles good when engine is cold but starts surging when hot. Have to slip tranny into neutral and rev it up a hair to keep it running. When rpm is above 900, engine run strong. Any ideas? I appreciate all the help. F

Reply to
fireant
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Will it idle in park?

Whitelightning

Reply to
Whitelightning

Does this happen when engine is hot, cold, both? What is fuel pressure doing while this is happening? Did you change the O2 sensor?

Reply to
cmplx80

Did "the shop" have any ideas?

Reply to
Meat Plow

Cold engine idle is almost normal. Hot engine idle is when surge is most noticeable. Feels like the computer is trying to balance a bunch of conflicting signals and then it dies. Easy to restart.

Reply to
fireant

Reply to
fireant

"the shop" said they "tested everything" on the fuel injection side, said they didn't find anything. This is the same shop that told me I needed new ball joints and a wheel alignment when I specifically said surging idle. They are not getting another red copper coin out of me.

Could it be the distributor?

Reply to
fireant

Try the idle control sensor, I don't know about a 91 model but on a 92 model it is on the passenger side of the throttle body and has a plug with 4 prongs plugged into it. It is real easy to replace.

Reply to
CorFowler

Have it sc>>

Reply to
Meat Plow

Have you changed the temperature sensor?

Reply to
cmplx80

Yes. no change in condition. replaced the rotor in the distributor. Problem is about 75% gone. Probably should have changed out the entire distributor but only paid $15 for parts plus labor so I thought that was good.

Reply to
fireant

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