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95 Blazer rough idle

Old  June 12th, 2009, 8:59 PM
Ok I'm starting to think that I may have a VCM problem, SES light came on today so I pull out the Tech 2 scanner and DTC PO134 Heated oxygen sensor No activity detected B1 Ssensor 1 so I pull out the meeter and disconect the O2 sensor Reference Voltage is supposed to be .45volts and as low as .32 volts depending on the meter used Mine is .26-.28
on both sensors so check connectors wiggle them around with no change,clear the DTC to see if it will happen again. I take the truck for a ride and the service light SES light is back on again check DTC with scanner and have 3 more stored PO340 camshaft position sensor
circuit malfunction, PO441 Evap system incorrect purge flow, and P1406 EGR pintle position error My EGR is 1 week old with it throwing all these codes and a lower than allowed reference voltage on my O2 sensors I think my truck needs a new brain because although i still have a rough idle the truck runs like New
Any thoughts??

Old  June 14th, 2009, 5:46 AM
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There is a way to test the mapsensor! Do you have a Haynes manual? Mudmaniac how do adjust TPS? I don't think I did that when I replaced mine?
There are a couple different types of TPS, one of them fits over the cross shaft end and another has a tab at the end of the shaft. They both have very limited adjustment before you tighten the mounting screws. It should be at .65 volts when idling and 5 volts at WOT. The Holley TB has a much easier adjustment and an idle adjustment screw as well.

Old  June 14th, 2009, 9:35 PM
Ok fixed the Multiple DTC's replaced fuse #5 for O2 EGR and Evap codes
Gonna change fuel filter and tune up tomorrow and hopefully rough idle goes away but have ordered a new MAP sensor and IAC from rock auto other than the ICM that's the last original 95 parts left on the vehicle and both can affect idle

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