engine dies after highway driving

[Judy]

I recently moved out of state and after the 700 mile drive, my 1993 Bronco has been acting up. I now live in the mountains and the bronco is not handling the hills well.

Upon start up, everything is fine but after driving on the highway 15-20 miles stopping for errands and restarting the truck, the engine starts to idle VERY low when I stop or slow down. The engine has died a few times and I can restart as long as I am able to rev the engine and keep the RPMs up. In order to prevent the engine from dying, I rev the engine to keep the RPMs over 2000 when at a stop.

My husband changed the spark plugs and put on a new distributor cap and rotor and wires. The problem continued. He then added a pure ethanol gasoline additive, Sea foam (not sure on spelling) after that, the low idling stopped and the truck was running well. Then I let the truck sit for a week or so and the next time I went into town the engine started idling low on the way home again.

I did not use all of the gas that had the additive in it. I don't know if I should get another can of the additive and drive daily until the tank is empty.

My husband is wondering if this could be a problem with air intake. I am not currently working so money is a little tight so we are trying what we can while saving in order to take the brocno into a shop.

Thanks for any suggestions.

 

[chuckles1856]

Greetings!

No check engine light I'm assuming?

The last time it got cold my '91 decided to get me about a block away and then die. It was almost like it got flooded cause it wouldn't restart until I let it sit for a good 8 hours.

How old/dirty it the air filter? Dirty filter could restrict air flow. New filter is like $10.

 

[Krafty]

a moderately clogged fuel filter will also cause these issues and will not turn on the check engine light.

 

[miesk5]

yo J,

Although a check engine light may not be on continuously while driving, check for Codes anyway.

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

http://broncozone.com/topic/14269-code-reader/page__pid__74587__mode__threaded

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.

Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

Look Codes up in my broncolinks.com site using the new Search function.

And Post em here according to:

KOEO

&

KOER

===

re your, "husband is wondering if this could be a problem with air intake"

Has the intake sys been modified or missing pieces?

and as Chuckles and Krafty advised; it filter is dirty, replace it

This is by Ford for Low/Slow Idle:

Check air filter.

Check air intake system.

Inspect Intake Air Temp (IAT); (Air Charge Temperature [ACT] prior to 1992)

This sensor is responsible for inputting to the Electronic Control Unit (ECU) the temperature of air stream in the air filter or intake manifold. The sensor is used both as a density correction for air flow calculation and to proportionthe cold enrichment fuel flow calculation and to proportion the cold enrichment fuel flow. located in the intake manifold , driver's side

Location pic



Source: by SeattleFSB

Testing, Voltage Chart @ Temperatures



Check for low battery voltage. Quick Check If horn(s) worked fine before, do they work as well now while having low idle condition? Same for turn signals while having low idle condition?

Check vacuum lines for leaks or wear. Joe has spome leak tests in his code check article above

Inspect electrical connections, wires, and harnesses

Check coolant and engine oil levels.

Check thermostat for proper operation.

Check EGR valve sticking.

Check PCV valve for correct operation.

Check for restricted exhaust.

Check for sticking or binding throttle linkage.

Check for throttle body contamination.

Check for proper idle speed setting.

Check for correct fuel pressure.

Check for fuel contamination/quality.

Check fuel filter.

Check for correct base timing.

Check distributor cap, adapter, and rotor.

Inspect spark plugs and plug wires.

Inspect ICM (ignition control module) for damage.

 

[miesk5]

yo, As for the Check Engine Light (CEL) being Lit;

Check Engine Light (CEL) comes on when the electronic engine control system is not working properly.

The CEL indicator comes on briefly when the ignition switch lock cylinder is turned to ON, and should turn off when the engine starts.

If the check engine warning indicator does not come on when the ignition switch lock cylinder is turned to ON or if it comes on while the vehicle is moving, the system is malfunctioning

If the CEL does not light up at all when starting it; then suspect that someone removed it or CEL circuit needs repair

 

[Rons beast]

Hey Judy,

Ditto M5, on checking for codes. I had a similar problem on my 96....no CEL but a pending code of 171. Turned out to be the EGR valve sticking after some driving. It was open just enough to make idling a problem. After trying to clean it and the problem reoccuring after awhile, I just got a new one. It was due on a vehicle that was 15 years old.

Good Luck

 

[Judy]

Thanks everyone. We will try this tomorrow when hubby is off again.