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High idle, rough idle, low coolant temperature.


atikovi

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Some of these might be related but I though I would ask for suggestions. My '88 has 189,000 miles and when you first start it cold, the engine speed seems like it's over 2500 rpm, and then after about 10 seconds it settles down to 1300 rpm. I can't imagine that's too good for a cold engine to rev so fast before oil has had a chance to circulate. Once it "warms" up it still idles high at 800 rpm in gear. It also feels a bit rough both in gear and neutral. On the highway the engine temperature is around 140 degrees in 45 degree weather, and even in suburban traffic it doesn't get much above 160. I assume it idles high because the computer thinks it's still warming up? I'll check the thermostat first for the high idle but what would cause the idle to feel rough and to be so high when first started. Leaking EGR valve? Dirty injectors? It has new plugs, wires and the throttle body was cleaned.

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Good suggestions. I cleaned the IAC valve tip and the passages in the T.B. They had a light bit of soot build up. Seems to have lowered the idle a bit when started cold and feels a little bit smoother. A new Bosch 02 sensor is $15 so I'll also replace that. Can you get to it from the top?

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Yes, look straight down the firewall, just below the heater blower motor. Suggest you get a slotted socket designed for O2 sensor removal. Not that expensive. Oh yea, don't forget a socket extension.

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7/8 box end wrench works well on the 88. There is room to slip the wrench over the sensor wire and push/pull from under the power steering pump. It doesn't look like it at first glance, but it works. It helps to have the motor hot to loosen the O2 sensor if the last person didn't use can't seize. Most sensors come with the lubricant already applied now.

2. don't rule out a bad plug wire to cause rough idle. I haven't found a reliable way to check them except to replace them. I have cut them afterwards and found the carbon to be burned and cracking 4 to five inches up the wire.

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I changed the O2 sensor this morning but it didn't make a difference. At least I got another maintainence item checked off my list. I'll probably pull the injectors and send them off to be cleaned. Nothing much else to do and with 190K miles they probably need a cleaning anyway.

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