Rough Idle - Stalling - Different from Other Issues Found

[wdl836]

I've searched the forums and couldn't find a similar issue, so I'm going to start a new thread for this question. If it has been answered before, please accept my apology.

I have a 1995 EX, 4.0, 4x4. The odometer stopped turning in 2005 with 208k. I’ve never had many problems. I had to replace the fuel pump about 6 months ago.

I’m having a problem with re-starting my EX after it has been sitting for between 20 and 35 minutes. The other posts that I’ve found say they have this issue from a cold start or at red lights. It starts perfectly if it’s been sitting for more than one hour. I’ve documented the time frames on my numerous trips to Lowes for work. I have to make each trip short, or deal with the rough idle and stall.

Each time this happens, I turn the ignition; it starts, idles very rough and then stalls. I then turn the ignition to off, remove the key and repeat the process for approximately 3-4 more times. To get the truck moving, I have to put it in neutral, start it, rev the throttle and quickly put it into drive. It will run rough for a few seconds and then run perfectly.

I took it to a friend of mines shop to check the codes and got nothing.

Some similar (cold start or red light) posts have given a few solutions, but I wanted to see if anyone has ever had this exact issue. Their solutions were; fuel filter, IAC valve (clean or replace), fuel pressure regulator, exhaust gas recirculation valve, mass air flow sensor or vacuum hose.

Any ideas where I should start? Thank you in advance for any guidance. We don’t have a lot of money to spend on guess and check repairs.

 

[fixxxer]

Checking for vacuum leaks would be my first step and it can be done cheaply, especially if you can rent or borrow a hand-held vacuum pump or you can spray some starting fluid around the vacuum lines and fittings once the truck is running. If there is a vacuum leak, the system will suck in the ether from the starting fluid spray and it will change your idle speed and the smoothness of the idle when you hit a leak. Fuel filter is normal maintenance and not expensive to replace, IAC valve I consider normal maint. to check and clean. If it requires replacement, it can start depleting your wallet. FPR is easy to check just by pulling the vacuum hose and checking for fuel in the vacuum line. The EGR/DPFE system is a little more complicated and will definitely cost some $$ if you have to replace. When you check your vacuum lines, check for cracks in the hoses and loose or missing hose connections, replace any that are "iffy". Cleaning the MAS/MAF is easy and they usually either work or don't. Check for air-leaks at both the air-filter box and the throttle body, cracked rubber hoses, loose clamps and so on.

 

[wdl836]

Thanks. I'm on it tonight.

 

[96eb96]

I've searched the forums and couldn't find a similar issue, so I'm going to start a new thread for this question. If it has been answered before, please accept my apology.

I have a 1995 EX, 4.0, 4x4. The odometer stopped turning in 2005 with 208k. I’ve never had many problems. I had to replace the fuel pump about 6 months ago.

I’m having a problem with re-starting my EX after it has been sitting for between 20 and 35 minutes. The other posts that I’ve found say they have this issue from a cold start or at red lights. It starts perfectly if it’s been sitting for more than one hour. I’ve documented the time frames on my numerous trips to Lowes for work. I have to make each trip short, or deal with the rough idle and stall.

Each time this happens, I turn the ignition; it starts, idles very rough and then stalls. I then turn the ignition to off, remove the key and repeat the process for approximately 3-4 more times. To get the truck moving, I have to put it in neutral, start it, rev the throttle and quickly put it into drive. It will run rough for a few seconds and then run perfectly.

I took it to a friend of mines shop to check the codes and got nothing.

Some similar (cold start or red light) posts have given a few solutions, but I wanted to see if anyone has ever had this exact issue. Their solutions were; fuel filter, IAC valve (clean or replace), fuel pressure regulator, exhaust gas recirculation valve, mass air flow sensor or vacuum hose.

Any ideas where I should start? Thank you in advance for any guidance. We don’t have a lot of money to spend on guess and check repairs.

My money is on the IAC, there is a documented problem with "timed no starts." Take it out, clean it with MAF cleaner (the grey can) and see if it improves. Try not to get the cleaner in the motor end of the IAC.

You can also clean your MAF too with that stuff.

If cleaning helps the problem in any way, you bought some time because the IAC is on its way out. Especially a 15yo one. I suggest a Motorcraft replacement from Rockauto, also look for the 5% discount.

 

[wdl836]

Thanks to all. I cleaned the IAC last night and then ordered a new one from Rockauto. Thanks for the heads up on the discount. I'm going to clean the MAF tonight and replace the fuel filter this weekend.

 

[2000StreetRod]

IAC valve, MAF sensor, fuel filter, ECT sensor

I agree with previous posters: cleaning the IAC valve and MAF sensor and replacing the fuel filter are regular and essential maintenance tasks. Your problem seems to be related to a warm start which is frequently caused by a defective engine coolant temperature (ECT) sensor. I suggest that you test the ECT sensor.

The EGR system is disabled at idle unless your EGR valve is sticking open.

Cleaning an IAC valve does not always restore its functionality. It is an electo-mechanical device that is prone to failure. After testing the ECT sensor you may want to perform the Idle adjustment procedure.

 

[96eb96]

Yes, a good scan tool (not a code reading toy) is important, you can quickly check that all the sensors are reporting correct information. For around $120 you can get one for a laptop, it will pay for itself in the first use. Knowing ECT(coolant temp), IAT(air temp), MAF V(reported air flow), BARO(MAF computed air pressure to verify its health), EGR(determine if there is light, non code setting flow at idle), Fuel trims, can save many headaches! My scan tool can even verify if the Crank position sensor is reporting data in a no start.

My scan tool gives me lots of peace of mind that everything is ok.

 

[FexplorerV8]

Yes, a good scan tool (not a code reading toy) is important, you can quickly check that all the sensors are reporting correct information. For around $120 you can get one for a laptop, it will pay for itself in the first use. Knowing ECT(coolant temp), IAT(air temp), MAF V(reported air flow), BARO(MAF computed air pressure to verify its health), EGR(determine if there is light, non code setting flow at idle), Fuel trims, can save many headaches! My scan tool can even verify if the Crank position sensor is reporting data in a no start.

My scan tool gives me lots of peace of mind that everything is ok.

what scan tool do you use

 

[96eb96]

what scan tool do you use

http://obd-2.com/

Make sure to buy at least a "dual combo" with PWM and ISO. It will read ABS and Body codes too (GEM, Climate control).

"DOUBLE COMBO - contains any two of the above networks $142"

It is the only scanner I know for under $1000 that can read and log ford ENHANCED codes(up to 900 on some cars!), ABS, Airbag. Most OBD scanners give you 10 obd parameters in the stream.