Tach stopped working for a few minutes

[Random]

Ok, went to start the sho today. it wouldnt start. just kept cranking over. Then I started getting a fair amount of backfire as I was cranking it. it finally started, but the tach didnt work. I drove to work anyways. The idle was very choppy while waiting at lights though. then the tach started working again and the idle was fine. and I havent had the problem again. it has done this a few times in the past few months. I am trying to diagnosis the problem.

I was thinking Camshaft position sensor. I already changed the crank position sensor. I know my O2 sensors need replacing, but I didnt think this could cause this exact problem. whats your idea?

 

[rendyx]

You might check your alternator/battery. My SHO had similar problems when it was low on juice.

 

[Random]

Both battery and alternator are less than 2 months old.

also, how hard is it to replace the camshaft position sensor?

 

[MOSHO92]

My 92' did exactly the same thing when the cam sensor went out.

 

[gas it]

It's the Cam Sensor. Check for codes. The O2 sensors aren't read by the EEC til the engine has run for a couple minutes.

 

[projectSHO89]

Disconnect the cam sensor. Try starting the engine. It may take 2 or 3 tries.

When it starts, you will have no tach, so don't be alarmed.

Drive the car and see if the drivability issues are resolved. If so, replace the cam sensor. If not, reconnect it and continue troubleshooting.

The cam sensor is an easy (relatively) replacement. It is available from AutoZone as a Wells F134 for $29.99 for all 3.0 and 3.2 SHO engines.

Steve