misfire code I pulled all plugs and no 2 and 4 had a closed gap.


I have a 2004 Nissan altima 2.5l in the shop. and had a misfire code i pulled all plugs and no 2 and 4 had a closed gap. i ask the customer if a tune up had been done any time and they replied no ,, so it is all oem equipment. so how do i explain the spark plug messing up like that. i threw as new set of ngk’s in it and now it is coming back with the same problem 


The only explanation is that something inside the cylinder caused the spark plugs to do that. I would recommend to check compression.  And check for timing belt tensioner failure. If the timing was able to fluctuate, it could allow the piston to hit the plug.

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Looking to install reverse beepers on our fleet of cars and trucks


Looking to install reverse beepers on our fleet of cars and trucks also vans does chevrolet use multi plexing wiring to reverse lights or do i need to install a relay? Pick ups S10-3500 series and vans all range from 1999-2008


No need for a relay. Just Ground it to the frame and connect your positive to the power supply wire on the back up light bulbs ( you can connect in the wire harness ). No multi plexing to the reverse lights.

2002 camry le a/c light on dash flashes


2002 Camry le a/c light on dash flashes occasionally and does not cool. Any Suggestions? Checked freon level OK. Heard it may be a relay? Already Tried: checked freon charge 


The light flashes because the compressor speed is not matching the engine speed. This is usually caused by something not turning the magnetic clutch on for the compressor. The magnetic clutch relay is usually the most common problem. See the link below.

Technical Service Bulletin

the car acts like the clutch is slipping. 2007 ford mustang


2007 Ford Mustang with a saleen supercharger. spec 2 clutch. when I power shift the car from 2nd to 3rd the car acts like the clutch is slipping. I installed the heavier duty after market disc and pressure plate but the problem still exist. The car only has 9200 miles on it. driven once or twice a week. It has been to the drag strip twice but with the engagement issue it is not very competitive. I have heard their is an issue with the hydraulic slave mechanism?


Your tires may just be loosing traction. I had a customer with a 2003 Lightning that complained of a transmission slip. I could not verify the problem, so I rode with the customer. He treated the gas pedal like an on/off switch, and every time he lit the tires up, the tach would spike and he said, “see, the trans is slipping!” To my surprise, it would break the tires loose grabbing third gear. Since you are power shifting and you have a supercharger, I think your tires are loosing traction, not your clutch. If it was slipping, it would also slip in higher gears.

Should I keep the dexcool antifreeze in my vehicle?


I have a 2001 Chevrolet Impala 3.4. Should I keep the dexcool antifreeze in my vehicle? Or should I change it to the green stuff, perhaps the prestone. Currently my plan is to remove the dexcool by pulling the radiator plug out and draining it each time my car runs until it comes out clear. Then I will probably switch over.    Is it advisable not to go green? The class action suit against dexcool is something I am worried about. Someone said I should be draining where the thermostat hose is, but I cant find it. Information about the pros or cons and your suggestion about what coolant I should use would be appreciated and also the location of the thermostat would be helpful. 


It will not hurt to change over to the green anti-freeze. How I would do it is similar to how you are thinking. Loosen drain at bottom of radiator, Remove the fill cap, Put a water hose in and turn the water on, let it spill over as it won’t hurt anything. And start the engine, let it run till the fluid is clear water coming from the drain. Turn engine and water off.

Let the water drain from radiator. Tighten drain plug. Fill with 50/50 green anti-freeze/water mixture. Start engine and top off coolant level. The thermostat is located at the end of the upper radiator hose. There is a small screw here (brass, be gentle) unscrew it a couple of turns and once the engine warms up some fluid should come out of it, this helps bleed out the air from the system. You may need to do this a few times to get the air out. Then you should be good to go.

BE Careful as the coolant can get extremely hot and burn you. If you are not comfortable doing this yourself, have it done! Shouldn’t cost you $80.00 

2002 Bonneville – manual a/c – compressor clutch does not engage


2002 Pontiac Bonneville – manual a/c – compressor clutch does not engage – trying to troubleshoot – where should i start – refrigerant pressure is fine. Already Tried:
swapped a/c clutch relay w/another relay of same part number in fuse box.


In the underhood fuse block, you have both the Clutch Relay, and the A/C Clutch Fuse. It is important to not only check the fuse…you also need to know that there is 12volts on both sides of the fuse. This can be checked with a 12 volt test lamp.

If the AC Clutch Fuse is bad, you may have a shorted AC Compressor Clutch Diode. Keep in mind, that the Powertrain Control Module controls the AC clutch engagement. The PCM looks at other inputs before it will allow clutch engagement. Therefore, you will need to verify that there are no trouble codes stored in the PCM that may cause the PCM not to allow AC clutch engagement. The AC refrigerant pressure sensor must also be functioning for compressor clutch engagement.

Below is a bit more information that is important.

The purpose of the air conditioning (A/C) system is to provide cool air and remove humidity from the interior of the vehicle. The A/C system is engaged when the A/C switch is pressed and the HVAC control module is in any mode except OFF. The A/C system will operate regardless of the temperature setting, as long as A/C line pressures are between 255-2968 kPa (35-430 psi) .

The HVAC control module receives power from the rear fuse block on the ignition 3 voltage circuit and battery positive voltage circuit. The ground circuits provide ground for the module.

When an A/C request is selected, the HVAC control module sends a class 2 message to the dash integration module (DIM). The signal is send through the class 2 serial data circuit. In order for the powertrain control module (PCM) to internally ground the A/C clutch relay control circuit, the DIM and PCM must communicate to each other over the class 2 serial data circuits. The PCM monitors A/C refrigerant line pressure and engine coolant temperature. This information is placed on the class 2 serial data circuit and is monitored by the DIM. The DIM looks at the A/C line pressure, engine coolant temperature and battery voltage along with the A/C request input from the HVAC control module. The DIM will request A/C operation from the PCM if these parameters are within normal operating limits and the HVAC control module is requesting A/C operation. The PCM turns ON the A/C compressor by providing a path to ground through the A/C clutch relay control circuit for the A/C compressor clutch relay. Power is provided to the A/C compressor clutch relay internally of the underhood fuse block. Once the relay closes its internal switch, power from the battery is provided to the A/C compressor clutch through the A/C compressor clutch supply voltage circuit. Whenever the compressor is turned OFF, the A/C compressor clutch diode prevents a voltage spike from burning up the compressor clutch coil. The ground circuit provides a pathway to ground for the compressor. The A/C clutch relay control circuit is grounded internally within the PCM. The A/C compressor clutch will be shut down under high electrical loads. The blower motor speeds will be affected first, then the compressor will be turned OFF, unless system is in defrost mode. The HVAC system will operate as if the OFF switch has been pressed. When this happens, the driver will still have the ability to override this mode.

The PCM will engage the A/C compressor clutch any time the engine speed is below 5000 RPM and the A/C is requested unless any of the following conditions exist:

  • Throttle angle is at 100 percent (WOT).
  • Vehicle launch, acceleration from a stop.
  • Idle quality
  • The A/C refrigerant pressure sensor is more than 2968 kPa (430 psi) or less than 255 kPa (35 psi) .
  • Engine speed is more than 5500 RPM .
  • Engine coolant temperature (ECT) is more than 121°C (250°F) .
  • Transmission shift
  • Engine torque load