Question about 1990 Pontiac Trans Sport

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Vehicle takes 5 minutes to idle by itself. Why?

Vehicle failed E check because of high levels of Nitrogen Oxide meaning vehicle runs too hot. Temp guage is normal. When vehicle is just started it has a hard time idling but after a few minutes of manually giving it gas it runs fine. What is most likely the problem a heat sensor?

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An inadequate functioning egr system.The exhaust gas recirculation valve uses spent exhaust gases to line the cylinder walls with burnt gases.The purpose of this is to keep the cylinder temperature lower to reduce emissions of oxides of nitrogen.

Posted on Jun 01, 2010

  • Jonathan S
    Jonathan S Jun 01, 2010

    The vehicle temperature may be ok what the e test is referring too is internal combustion temperature is too hot. The egr also can cause a rough idle if it is stuck open from carbon build up keeping the egr pintle from closing.



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I have a 1994 chevy silverado c1500 v/6 4.3 litre and failed smog for high hc levels st idle . what should i do before i take it back to try and smog? ive already done complete tune up.

as long as you have no check engine light on change oil, air filter. pep boys sells a product called guaranteed to pass add to fuel make sure car is hot when you go back for emission test cold car has high hc levels it also helps to post the hc level you tested at and the limit on your receipt hope this helps

Apr 08, 2016 | Cars & Trucks

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Why does my heater blow cold at idle

  1. You May perform the following with the vehicle in park or neutral with emergency brake firmly on.
  2. Check the coolant level when the engine is cold. With proper coolant, fill radiator to top and reservoir to the COLD LEVEL mark.
  3. With radiator cap off, start the engine and let it idle.
  4. After 10 minutes of running at idle, you should observe a coolant flow in the radiator.
  5. if you observe flow, reach inside car and turn on the heater to high and max temp.
  6. Now observe the radiator fill level. If the level has dropped substantially, add more coolant to the system to the top. the coolant should be warm or even HOT. If it fails this observation go to #8
  7. If so, replace the caps on your system. Take the vehicle for a short drive and check your heat at an idle inside the car. It should be normal if you have made all the above observations.
  8. If coolant remains cool or cold, it is likely a faulty component. A bad thermostat will cause this symptom. Faulty servos or valves that control the flow of air in the cab.
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Dec 18, 2015 | Cars & Trucks

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89 cutlass cierra crank but wont start when wet out unless gas pedal is pushed

This should be a drive by wire vehicle meaning it has a cable for the throttle body. First thing would be to see if any error codes can be pulled up (most parts stores will do that for free.) Drive by wire versus the late model that use electronic control for the idle have a IAC or idle air control which when first started controls the idle air intake--all air is run by it to idle the vehicle when cold--

Usual symptoms are rather high idle when cold engine or even idle and RPM jumping up and down and stalling when cold.

Another way if idle does drop when cold is tapping the gas--engine will still run until hot. Means not usually a fuel pump issue.

You could also have if the vehicle is fuel injected a dirty Mass air flow sensor, a throttle position sensor, etc.

These can be if the vehicle has them cleaned using a special zero residue spray cleaner.

First have it scanned to see what if any errors it shows--the computer.

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I have a 1990 geo metro that has been sitting for a few years in a garage in Colorado, we now have it in Texas but it wont pass emissions testing d/t high levels of nitrogen oxide?. We replaced the...


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this would get everything up to temperature and burn out anything left in the exhaust system, and allow the engine management system to adapt to normal running as it is probably reset itself to default settings in storage.
also change the oil, oil filter, and air filters first.
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Check your coolant level. My mother was complain about the same thing last month. I checked it out for her figuring it would be a bad thermostat. Removed the radiator cap and started adding fluid to it. 2 gallon later the problem was solved. No leaks, just years of not bothering to check it let the level fall so far that there was no longer enough fluid to circulate through the system properly, it would only get warm when the cars temp hit boiling point. Then it would bubble up enough to circulate into the heater core and drop the cars temp down for a few miles the the heater would get cool again and repeat. Hoping your problem is as simple as that.

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Need to add tranny fluid to '99 Rodeo, but where??

Overfilling will cause foaming, loss of fluid, abnormal shifting and possible damage to the transmission.
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2. Check fluid level with engine running at idle.
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3. Move the selector lever through all gear ranges.
4. Move the selector lever to “Park”.
5. Let engine idle for 3 minutes and open the overfill screw (1).
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7. Let engine idle until a fluid temperature between 32C (90F) and 57C (135F) is reached, then close the overfill screw (1).
Torque: 38 Nm (3.9 kg·m/28 lb ft)
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CAUTION: Do not open overfill screw with engine stopped.
 Immediately after driving at sustained highway speeds.
 In heavy city traffic during hot weather.
 If vehicle is towing a trailer.
If the vehicle has been operated under these conditions, shut the engine off and allow the vehicle to “cool” for thirty (30) minutes. After the cool down period, restart the vehicle and continue from step 2 above.


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