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Discussion Starter · #1 ·
When my car is warming up until the stock temp gauge needle hits the first tick on the gauge) giving the car gas causes the RPMs to drop and the vacuum to go up (usually up to -5, depending on how much gas and if you hold it there). When this happens the exhaust spits out smoke/lots of exhaust, although it's tough to tell the color because it's cold out (and the condensation makes it white sometimes), I think it's black when you open the throttle.

I live in Boston, so it's cold here right now. No mods have been added to the car and I replaced every seal on the engine about 10K miles ago. It has 167,000 miles on it.

The last strange thing is that after the car has warmed up, when coming down from an RPM higher than 1500, the RPMs drop to 300-500 for a second or so, and then struggles back up to the usual 950-1050 range. My MPG has also dropped to less than half of what it usually is...

Does anybody have any ideas on these two issues? I have to think they are somewhat related to some sort of Air/Fuel control...perhaps the AFM? Throttle Position Sensor? I'll be testing the AFM later today to see if it's within specs.

Thanks,
Andrew
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Discussion Starter · #8 ·
billwot, is the coolant temperature sender the same as the coolant temperature sensor?

I know the temp sender is on the "water outlet and housing" and connects to the wire that gives the temp gauge on the dash its reading. Are they the same?

-Andrew
 

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ramicio said:
ok...then i have the same SYMPTOMS, except the smoke.
Not trying to be argumentative, but his descriptin specifies the problems occur during start-up/ warm up, not all the time. He most likely has a problem with the cold start enrichment system. That does not sound like the same rpoblems you are describing.
 

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abinns said:
billwot, is the coolant temperature sender the same as the coolant temperature sensor?

I know the temp sender is on the "water outlet and housing" and connects to the wire that gives the temp gauge on the dash its reading. Are they the same?

-Andrew

No. The temp sender, whcih drives the gauge, has no effect on engine control. The coolant temps sensor is an input to the ECU, and plays an important role in matching A/F to conditions. The ECU adds fuel to a cold engine, then begins to lean it out as the engine comes up to normal temp.

Obviously, if the sensor does not provide acurate data, the ECU will be unable to provide the necessary fuel mixture.

bill
 

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and that is how mine is tooo...when i first start it up, and it's all the way cold, it runs fine. once the temp gauge reaches just over the bottom line, it acts up. then once its warm it drives fine. lacks a little power and hesitates a tad, tho. thing is i replaced the coolant temp sensor, o2 sensor, the whole afm for a known good one, and it does spec out to be right. the wires, cap, and rotor are less than a year old. plugs are basically new and gapped correctly. the coil is like 1.5 years old. no boost or vac leaks anywhere.
 

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abinns said:
When my car is warming up until the stock temp gauge needle hits the first tick on the gauge) giving the car gas causes the RPMs to drop and the vacuum to go up (usually up to -5, depending on how much gas and if you hold it there).
ramicio said:
when i first start it up, and it's all the way cold, it runs fine. once the temp gauge reaches just over the bottom line, it acts up.
See the difference? His malfunctions BEFORE it begins to warm up, and your malfunctions AFTER it warms up.

His is probably too lean on start up (no cold start enrichment), and yours is probaly too rich after it begins to warm up (does not lean out as engine warms up)

bill
 

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the bottom line as in the bottom of the gauge. the needle does rest almost 1/4" below where the gauge scale starts. his statement means that the car acts like that until it hits the first tick on the gauge. as does mine. anyway...i replaced the coolant temp sensor with a non-oem (parts store type.) before i replaced it, i went to unplug the old one, and the whole insides just fell out of the brass canister it is in. so i figured if it fell out and was in that bad of a shape, it was clearly out of spec. put the new one from the parts store in, and not a thing changed with the way it ran. and i have been keeping the car tuned up too.
 
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