91 c1500 stutter on acceleration

[badass66ss]

Ok, so I checked all grounds and voltage readings at the ECM... Everything seems to be in the operating ranges listed on the pin chart. So I again am at a loss. Any ideas???
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[mountie]

Originally Posted by badass66ss

Ok, so I checked all grounds and voltage readings at the ECM... Everything seems to be in the operating ranges listed on the pin chart. So I again am at a loss. Any ideas???
Posted via Mobile Device

Last year, when I was frustrated, solving a sluggish ignition/acceleration, I went to a friend's shop that had a Snap-On analyzer, it showed what was good, so I could focus on the glitch, which was a failing ECM & coil.

(The coil was the OEM style MSD replacement, and it wasn't old.)

[ChevyTech]

Originally Posted by badass66ss

Ok, so I checked all grounds and voltage readings at the ECM... Everything seems to be in the operating ranges listed on the pin chart. So I again am at a loss. Any ideas???
Posted via Mobile Device

Have you tried disconnecting and plugging the vacuum hose to the EGR and then taking it for a test drive?

Another thing you may want to do is test the compression. As these TBI truck get old it is becoming common to see the head gaskets fail between the center cylinders. When they first start leaking, often the engine will ping a little, and not run as smoothly.

[badass66ss]

Yes I tried the EGR test to no avail, the truck has good compression and the gaskets only have a few thousand miles on them.
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[ChevyTech]

Can you give us a better description of what is happening?

Does it misfire? Is it dropping a cylinder or two on acceleration?

Is it only on hard acceleration, or any acceleration?

Does it feel like the truck is trying to pull a train? No power?

Are the spark plugs Black with soot?

You replaced the ignition parts so you must have thought it was an ignition problem, is this correct.

Have you tried buying your fuel somewhere else?

Have you taken a fuel sample to see if there is water in the fuel?

[mountie]

The fuel........

Today's additives / Ethanol damages fuel systems, especially carburetors on motorcycles but also cars / trucks.

The jetting / injectors get corroded. If you let an engine sit without being started for a couple weeks, ..even a new tune-up will seem to go bad after an engine not running for a short while.

I have 2 expert tuners (one NHRA T/F & the other high performance motorcycles) told me to put either Sta-Bil or a similar product in the gas tank..... EVERY MONTH.!!

If you own a motorcycle, get Sta-Bil now, & put it in your tank, before it's too late if you have carbs.

I put it in my truck. It runs & idles great.

Something to consider......