93 chevy 350 hesitation

Jun 12, 2005 6 Replies
R

Have a 93 Chevy Silverado that has a problem with hesitating when accelerating. At steady 1000 rpm it also seems to be hunting.



It started when completing a cam change: Replaced cam and left off the negative battery connection to the engine (intake manifold). Cranked engine - no start. Found that wire was not hooked up so fixed that. Checked distributor cap - carbon connector in top burned out. Replaced that, replaced module in the distributor and replaced the engine coolant sensor.



Anyone have any experience with this? ECM need to be replaced? Have OBD 1 running data reader but not real experienced at this.



TIA Rex


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R

Checked fuel pressure 13 psi...

Would the ECM "partially" work? No trouble codes found.

Other ideas?

Thanks Rex

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W

How about a cat getting ready to take a dump. If you shake the exhaust does the cat rattle, or if you smack it does it sound like the "bed" is moving around inside?

How long does it take for the fuel pressure to leak down?

Whitelightning

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R

The catalytic converter is in good shape - truck has 82K miles.

Fuel pressure leaks down quickly after key is turned off.

Using Tech Scanner have found that spark advance is just the opposite as it should be. When accelerating the advance goes down to 5* or so - then letting your foot off the accelerator the timing jumps up to 30* advance.

Next question - which sensor(s) is/are malfunctioning?

TIA Rex

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