Flashing check engine light

DougNuts

Founding Member
Jul 11, 2000
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47
Georgetown Ky
Occasionally while on the highway my check engine light will flash on and off. I haven't found any pattern or any certain condition that causes it (like going up hill).

I installed a new O2 sensor, but that didn't solve the problem. I'm also averaging about 20mpg. :notnice:

Ran the codes the other day and I'm pretty sure it came out with something about the PIP sensor and the thermactor.

Any ideas?
 
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If it's flickering on and off, it might either be teetering along the edge of pass and fail in terms of the parameters for the light to come on, or there is a lose wire that causes intermittent signals (hence the flickering). Check your connections to the sensors in question from the code pull, and repair/replace as necessary.
 
.....sometimes moisture etc. can screw with it. It doesn't always warn of an actual bona-fide problem (hence the term "idiot light).

Cheap fix - remove bulb and sell at parts meet.


BTW, If it was a "smart" light it would know that you already checked the engine. DUH. :D


HD
 
How do you go about testing your sensors? I get a check engine light randomly as im driving down the highway from work...

I've ran codes many times and only brought up idle problems..

I get an average of 16.5 MPG..sad sad sad. car also smells like its running REAL rich sometimes...

Now that would lead to a bad o2 Sensor right? then why didnet the scaner bring that up? I also tryed unpluging the o2 sensor and drove the car and it dident change a thing.
 
MSM0075 said:
How do you go about testing your sensors? I get a check engine light randomly as im driving down the highway from work...

I've ran codes many times and only brought up idle problems..

I get an average of 16.5 MPG..sad sad sad. car also smells like its running REAL rich sometimes...

Now that would lead to a bad o2 Sensor right? then why didnet the scaner bring that up? I also tryed unpluging the o2 sensor and drove the car and it dident change a thing.


Exact same problem that I'm having. I changed the o2 sensor and that didn't do a ****ing thing for my milage or the light. If you figure it out, let me know. I'll take a good hard look at the car this weekend to see if I can figure anything out.
 
DougNuts said:
Exact same problem that I'm having. I changed the o2 sensor and that didn't do a ****ing thing for my milage or the light. If you figure it out, let me know. I'll take a good hard look at the car this weekend to see if I can figure anything out.

id check all the senors under and connected to the lower intake, aswell as the vaccum lines(which tend to be brittle and break). I just cleand under my intake (had the car on the lift, so i figured id clean it a little), unplugged them all ,cleaned of windblown oil and residue, and reconnected them. So far no check engine light, but that my just be a strand of good luck im having...i hit 3 green lights in a row today!
 
I got 24.6 mpg on a 256 mile trip tonight. That's after a new set of plugs and wires. Nothing to write home about, but that's the best I've gotten so far. A little more tuning and maybe I'll get it 25+!!

I still am getting the check engine light, it usually comes on as I'm cresting a hill or as I am going down one.
 
don't know whats up with my engine light, but it will go out if I rev the engine to somewhere around 3500, but for the most part it stays on all the time now, before that it use to go off and on when I rev'ed the motor but now its just on up till 3500.

anyways guess I will be checking all my sensors.
if anyone has a clue to what could be wrong I'd be so happy.

besides that the car runs fine.