I am probably gonna fix the Solenoid first but this is just annoying cause I can't find the part. Everywhere I look the part goes for like $240. WTF? All it supposed to do is put out a Vacuum pressure when the car starts and send it to the boost sensor right to help measure the density of the air for the a/f mixture right? ugh.

I hate Emissions on cars. They are what makes every car have terrible MPG when something goes afoul and I lose so much money by that lets not even talk how bad performance is ever since emissions been created. I mean if you wanna be a yuppy and say... "oh but the environment". Well what about all the old cars? Hmm? They have no emission systems and it is legal for them too cause of their age?

Anyway. I did a tuneup and everything under the sun. Except for o2 sensors and new coil packs(and yes cleaned EGR valve and replaced all gaskets in the IACV and throttle body) Also ordered a new K&N filter and I am not gonna use the oil and fixed my MAF and I still pull 16-17MPG. I want at least 20+ obv I am not expecting to get near stock of 24-26 cause the car is super old but at least somewhere where $20 bucks doesn't get me less than 90 miles lol

I also have a pipe leak under my header and I am getting that fixed today. I am not touching exhaust and never will unless I have a torch like I did in school lol. I am sure that will improve mpg a little bit because less oxygen is being sensed so less fuel will be thrown or something like that lol

 

Rock Auto has the MAP listed between $119 and $135. They call it the Manifold Pressure Sensor. You gotta have some Junk Yards near you...see what they want for one. $240 is crazy!! So is $118-$135 for a little friggen plastic sensor.

 

Well at this point I am pretty sure I need the other one as it says Solenoid but we will see lol

 

Plugs on the maf read 13.1 and 5.1 volts. So I know they are working.

 

Knock sensor?

 

Any engine codes pending or is the CEL light on.

 

CEL light is on. and when I clear it goes on either in a mile or when I turn the car off and back on.

 

What codes do you have?
How heavy are your wheels?
What PSI in your tires?
What size are your tires?
Whats your compression PSI?
Any fuel leaks?
What exactly is your MPG and driving style? City? Highway? Jackrabbit starts?

I find it hard to believe that you can point at two things and say it HAS to be one of them.

 

Why not? Those are the 2 biggest things that cause gas Mileage loss. Always have in a car and always will.

 

You didn't say what code you have. You only said the cel comes on again after clearing it. That's a serious issue right there.

 

1405 I think

 

1405 does not exist for us. There is no 1405 dtc, and p1405 is dpfe. We dont have dpfe.

 

sorry 1105

 

That's a transmission code. You're probably running without a 4th gear (if you're auto that is). That may be the culprit of your fuel consumption problem.

 

p1105 is not a tranny code lol

 

P1105 is way different from just 1105. What are you lazy to type a p?

 

my maxima gave poor mileage when two of the fuel injectors were faulty. easy test was to measure the resistance across the terminals of each fuel injector. look for differences in resistance when the car's ignition is in off position. replace any injector which has resistance near zero or resistance at top of scale. be sure to re-plug the connectors to the fuel injectors tightly. either a bad resistor or a bad connection to just one injector can cause in city mileage to decrease to 14 MPG from satisfactory MPG in city of 18.

 

yes

 

hmm. I shall take a look, I do have a somewhat rough idle.

 

1105 Is not P1105 lol.

 

HAHAHAHAHHA Holy ****, i see this thing running around South Houston all the time, 713 FTW

 

Are you just guessing because you "know" it has to be map sensor or solenoid?

 

Last month did the valve cover gaskets. Car was running rough.. RPM drops.. stalled when driving.
Anyways, when doing the valve gaskets noticed the plenum (exhaust manifold) gasket shifted to the right. Basically a vacuum leak. no seal on first bank from the right.
After replacing valve and plenum gaskets and cleaning all the ground car runs perfect now. No stalls no rough idle just drives.

Check your plenum gasket... not a typical problem and I don't know how it happened but def a problem.

 

hmm interesting, I;ll take a look btw the plenum. is only intake.