Rough idle and Lean

C

crjames3141

Member
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Mazdaspeed Protege
Have been battling an issue with my speed protege. While idling the car seems to idle abnormally low and rough over the past few months and my A/F is all the way lean. Been looking around and have tried cleaning egr with new gasket, new IACV, new Fuel pressure regulator, tried another fuel pressure control solenoid and now I'm ready to roll it out into the driveway with full coverage and the keys on the dash. Throwing fuel pressure regulator code and tumble control circuit code.
 
Is the FPR solenoid new or used? I would try another one and replace the VTCS solenoid as well (green plug). It sounds like a dirty or stuck EGR or dirty MAF. Could be a vacuum leak
 
Thank you for your feedback. I cleaned the egr and spring still compresses and everything I have a protege manifold I could pull the egr from that if the part numbers match up. The solenoid was off of a protege 5 and I forgot to mention I just got a brand new maf.
 
The solenoids and EGR are the same on the P5 and MSP. I think the used solenoid is also bad. You can try one of the other solenoids, on the bottom it will have a part number ending in 9090 or 9091 and as long as they match the one you are replacing it will work fine. Do you have a boost gauge? What is the vacuum reading at idle?
 
I'm working on getting my gauge with vacuum back. I stupidly put one in with no vacuum and only reads boost because it had a light lol. I'm gonna try to switch EGRs and see how that goes. I will get back to you tomorrow.
 
Tried the beautifully new egr that I had and no luck. Could primary o2 sensor be damaged? I had some wires that were brittile and I had to fix I tried to find the wiring diagrams for harness end of the o2 with no luck. Will try a new FPR solenoid if I can find one and is there any ways a crank sensor could be the culprit.
 
Crank sensor would throw a code. Have you checked for vacuum leaks and made sure the charge piping is tight, especially after the MAF? Cleaned the MAF?
 
Yes I pulled all of my vacuum lines and blew through them and they all retained pressure. Just got valve cover off to check timing. I barely ever have time for my baby Mazda anymore. Is there an indication of whether the crank is top dead sensor with the cams? Also I noticed the crank pulley is missing a tooth. Is this normal? I attempted to do boost leak test with one I built but I guess I'll just have to invest in one.
 
It is normal for the crank to be missing a tooth. The cams have markings that will point together, intake cam has an I and exhaust cam has an E and they will almost be touching with the crank at TDC.
 
MAF is new btw. If the crank sensor wiring has a questionable connection on one of them, could this be the issue without throwing a code?
 
Alright so from the beginning. The crappy idle issue started for a few weeks. I would be at a stoplight and the car would idle fine for a second and then drop a couple hundred rpms and go lean. However, at this point it would at least hold and idle. This was open down pipe at the time. Tied in my exhaust reset the ecu and then it went to s***. Won't hold an idle and wants to stall. What is the first thing that comes to mind? I'm missing something obvious as heck.
 
Does it misfire under load? It sounds like a vacuum leak, dirty MAF, dirty EGR, dirty IAC.
 
No misfire under load. New iacv, new egr, new maf, new injectors, blew through all my vacuum lines no leaks. I guess next step is to pull every piece of piping I have lol.
 
I used to have that problem, and what I did is simply put a bolt the size of EGR valve where it is located on the exhaust. No problems since.
 
You can cap the EGR at the manifold and cut the EGR pipe. As long as the pipe can bring in air you shouldn't get a check engine light, you can put a filter on the end of the pipe.
 
Okay so new info. I ordered this new maf from rock auto. Now it was the cheap one and says it works with my car but the sensor for it looks different and it no longer throws a maf code. Could this be a culprit?
 
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