94 Mazda B3000 Cooling Gremlins

[B3000SE]

Hey Everyone I have a 94 B3000 SE Extended Cab Auto Trans 2wd,I Just Replaced a sticky Thermostat because the truck took forever to warm up in the morning, I also Flushed the radiator,well after doing this it still takes awhile to warm up from sitting all day or night and the temp gauge moves up and down quite a bit and sometimes will go up 10 degrees past half on the temp gauge when its 45 degrees outside.I Bought a Quality($10) Thermostat with a Burping Valve on it,I have had no check engine lights and it runs rough when cold between 1000-2000RPM's (It Misses) ,This is new to me I haven't owned the truck very long and don't know much about Fords.Is this typical for this truck with age or do I have a Big Problem happening ? I would appreciate any help if I can Prolong or prevent a major repair.....


Every Ignition Part Has been Replaced

 

[TomB1269]

1st part did you bleed the air out of the cooling system. Note, the return to radiator hose runs over the alternator and makes it higher that the cap. You need to let it sit an run until the T-stat opens fully and that hose is firm with coolant running thru.
As for the rough running are you shure it under 2000, is it under load or idling? If idling, is it only when the air temp is low or also when it is a warm day? (points to Idle air control valve) Have you replaced the air filter? Are you useing an oil type (K&N, etc), have you try cleaning the mass air sensor with Mass air sensor cleaning spray?
Try these & let us know.

 

[Big Jim M]

Same as above.. You prolly didn't open the heater valve and fill the complete engine with coolant. This will cause bad running also as the air bubble causes parts of the head to get too hot...but the gauge doesn't show this extra heat.
Big JIm

 

[B3000SE]

I did run the heater before and as I refilled the radiator,It took me about 20 min or so to rid the air from the system as well as Replace the lost coolant and everything seemed fine and topped off.As Far as the Rough Running,I am using a brand new Fram air Filter,It runs rough at idle around 750 rpm's (Its been around 40 degrees or cooler in the morning and doesn't get much warmer here this time of year) And Under Minimum load between 1 and 2 thousand rpm's it sounds like it misses or cough's until it passes 2 grand until it warms up,Its weird,I Didn't want to fool with cleaning the any of the sensors because I still have to have it pass emissions this week and cant afford a check engine light to come on lol I might Have to wait a week or so before I can Try.

 

[Big Jim M]

Well in retrospeck after rereading your first post I'm seeing a 10* fluctuation in temp.. That should be considered normal. As for running poorly when cold that would probably be the choke enriching parts that are telling the engine it is already warm when it really isn't. So look to the coolant and air temp sendors that are possibly lieing to the computer.
Big JIm

 

[B3000SE]

Thank You Very Much Big JIm and to everyone who has taken time to help me.If Those 2 sensors or Senders had issues wouldn't that Theoretically make the check engine light come on ?

 

[Big Jim M]

Nope! Cause although it is a bit too lean it isn't leaner than the computer THINKS it should be..
Big JIm

 

[B3000SE]

Wow OK well is there a way to test these components or just replace them for good measure ? I really would hate to start replacing things blindly and wasting money,This day in age we need to save every penny LOL In My Opinion They Should note these kind of things In the repair manuals for the DIY Guys....

 

[B3000SE]

OK I just drove it 42 miles round trip,I live at 2600 feet in elevation and drove down to sea level Where the Outside Temperature was almost 60 degree's.The truck ran great down the hill and had more power than Ive ever seen It have,Temp Gauge never went haywire or over half it went to half and stayed there,As soon as I Got back up the hill The trucks temp gauge went between Half and Hot at around 45 degree's outside Temperature,This is weird what could be causing such an issue ? Could it be possible that the elevation be causing a sensor to Lie to the Computer ? This truck is driving me nuts !

 

[Big Jim M]

Ahh yes!

OK I just drove it 42 miles round trip,I live at 2600 feet in elevation and drove down to sea level Where the Outside Temperature was almost 60 degree's.The truck ran great down the hill and had more power than Ive ever seen It have,Temp Gauge never went haywire or over half it went to half and stayed there,As soon as I Got back up the hill The trucks temp gauge went between Half and Hot at around 45 degree's outside Temperature,This is weird what could be causing such an issue ? Could it be possible that the elevation be causing a sensor to Lie to the Computer ? This truck is driving me nuts !

You and I have a lot in common! MY TRUCK runs great downhill too! And then when I'm going uphill it takes more fuel and the temp goes up a little.. just like yours does.
Big JIm

 

[B3000SE]

Wow Big JIm I don't know if that's a good or a bad thing LOL I haven't owned The truck that long but couldn't pass it up when I saw it for sale ($1300) Now I'm Kinda wishing I Held Out For A Fullsize Chevy at least I know those trucks well and can work on them.The Little Mazda hasn't Given me A whole lot of confidence in it thus far with all the issues Ive had with it.