I have a 97 gmc with a 350 vortech. the van will run very rough, idleing up and down when first started. temperature doesnt matter. van could be warmed up or cold and it doesnt matter. it may take several minutes before it clears up. then while driving it seems to out of the blue cut out and start missing and feel like its running on 5 cylinders. if i shut down and restart right away it will smooth out and run normal after a mile or so

There are several possibilities for this problem. A "cold start" sequence is suppose to activate based on water temperature and the signal from the water temperature sensor. This makes the fuel rich and adjusts timing to make the engine run better when cold. It works like a choke only it is electronic.

There may be 2 sensors with one making the dash gauges work and the other doing the engine controls. If not 2, then 1 sensor would do the whole job.

Another possibility is an air leak in the fuel system which makes the system bleed dry overnight. It is far less common on gas engines but happens a lot on diesels.

Some earlier Ford engines from 1984 to I don't know when they stopped on trucks, would use a step-up solenoid on the accelerator bracket that worked off water temperature. Sometimes a bad water thermostat would make the temperature controls malfunction the other way (High idle, clicking, low idle) that would stall and engine as the temperature vary.

Try to get it running a bit to warm up the exhaust. Take a point and shoot thermometer and take the temp of the cat. If temps exceed 400 degrees I would start to suspect a plugged cat.

Check the help links related to this problem.Click the link below to go through its troubleshooting procedure :-----Idles rough and quits when gas pedal is pressed less? http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.html---------
Car won't start without hitting the gas pedal? http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-without-hitting-gas.html
-------Complete loss of brake pedal then all gets normal? http://repairhelpcenter.blogspot.com/2012/01/complete-loss-of-brake-pedal-then-all.html
------Car dies when gas pedal is pressed? http://schematicsdiagram.blogspot.com/2011/12/car-dies-when-gas-pedal-is-pressed.html
--------Pushing on the gas pedal, but the car slows down? Gas pedal to the floor and the car slows down?

http://technoanswers.blogspot.in/2012/02/pushing-on-gas-pedal-but-car-slows-down.html

---------

After replacing brake rotors and pads, brake pedal remains on floor? http://technoanswers.blogspot.in/2012/02/after-replacing-brake-rotors-and-pads.html

---------

accelerator pedal sensor? http://technoanswers.blogspot.in/2012/02/2009-chevy-impala-accelerator-pedal.html

-------

For rough idle issues and problem troubleshooting,go through the help links provided below :----- van idles rough?

http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html

---------
will not idle when cold?

http://technoanswers.blogspot.in/2012/02/ford-explorer-40-will-not-idle-when.html

----------
runs lean and idles rough?

http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html

-----------
Engine stumbles coming off idle when warm?

http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html

------------
Erratic idle on car?

http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html

----------
Low idle when cold out side?

http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html

---------
Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html

----------
Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

------------
Car overheats and Air blows hot at idle?

http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

------
While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

---------

This will help.

Thanks.

For rough idle issues and problem troubleshooting,go through the help links provided below :-----van idles rough?

http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html

---------
will not idle when cold?

http://technoanswers.blogspot.in/2012/02/ford-explorer-40-will-not-idle-when.html

----------
runs lean and idles rough?

http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html

-----------
Engine stumbles coming off idle when warm?

http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html

------------
Erratic idle on car?

http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html

----------
Low idle when cold out side?

http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html

---------
Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html

-----------
Replace Idle air control valve?

---------
Test Idle Air Control (IAC) Valve?

-------
Idle Air Control (IAC) Valve operation?

----------
Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

------------
Car overheats and Air blows hot at idle?

http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

------
While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

---------

This will help.

Thanks.

For rough idle issues and problem troubleshooting,go through the help links provided below :-----van idles rough? http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html---------will not idle when cold? http://technoanswers.blogspot.in/2012/02/ford-explorer-40-will-not-idle-when.html
----------runs lean and idles rough? http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html
-----------Engine stumbles coming off idle when warm? http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html
------------Erratic idle on car? http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html
----------Low idle when cold out side? http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html
---------Idle Air Control (IAC) Valve Replacing? http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html----------Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

------------
Car overheats and Air blows hot at idle? http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html
------While stop engine idles like cylinder missing? http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html
---------This will help.Thanks.

i have the same exact problem, i have replaced fuel injectors, idle position sensor, idle air sensor, map sensor, temperature sensor,. the only way i can make mine run ok. not great is unpluging the map electrical connector, and it still has no power if u gas on it but it makes it down the road and smells rich, if u find out let me know what the problem was i really love my truck and hate that it doesnt run right, [email protected]

yes a beginner can just follow the top rad. hose to the block use a 10mm socket to take the 2 bolts out. scrape the old gasket away put new gasket and high temp silcone on gasket and install new thermostat.

doesnt sound like the problem to me, check the oil make sure no water is in it, sounds like the head is cracked on the exhaust side and ur water is going out your tailpipe, so in turn would ruin your cat converter and make the truck run raggy

if it has the vortech motor the gas pump most likely went bad.

If it does not do it in park or neutral, it could be a number of things. One being a sticking Torque Converter Clutch solenoid (TCC). It could be that it needs a simple tune-up. How often does this problem happen?