97' 626ES 2.5-V6 tech & tuning help needed please

[Sinika74]

Hey people, I'm new here & this is my first post. I just got a 97' 626ES-V6 and I really like it but I'm having a few problems that I hope yall can help me with. First, when its at idle, the engine is randomly missing. Its quite harsh with hefty jolt with each miss. Rpm loss is negligable with each jolt ranging from 100-200rpm drop if any at all. The idle rpm is around 1200 but I believe the sticker under the hood said 800. That sounds low to me but wtf do I know heh. Also, at idle, the engine runs smooth "except for the jolts" for a few seconds and then runs as if it were only on 5 cylinders for an equal amount of time. This action is not random and has a rythem to it that is constant every time I drive the car. Under accelleration, the engine runs fairly smooth, however its getting HORRIBLE gas mileage. I'm only getting 240-270mi. per tank running mid-grade pump gas. Also, the 4 speed slushbox has a HARSH 1-2 shift...is this normal? Also, I was wondering if anyone knew any do it yourself mods that I could do to this car that would net any tangible performance or efficiency gains? Anyone know of some really great aftermarket parts that I could fit to this 2.5-V6 "engine family: VTK2.5VJGKEK"? I want to keep it a daily driver, but wouldnt mind hopping it up a bit. The car has right @ 78,000 miles on it, it has new NGK blue plug wires, "I havent checked to see if the plugs hav been changed" and a new air filter. Other than that, it appears to be well maintained and in stock condition. Any/all help would be GREATLY appreciated

 

[Protege52003]

how many miles on plugs, wires, filters, tranny fluid. maybe it just needs a good tune-up?

welcome to the board, too. not sure how much info you will find on the 2.5L, but there are some good people here......

the 2.5L is a nice engine.....my father has a 01' 626LX-V6 w/5-speed!
engine has almost 70K and he has only replaced the thermostat on her.

 

[Sinika74]

Not sure how many miles are on the plugs, I'd check them myself but its raining cats & hogs down here in Jackson. As far as the wires go, they appear to have less than 20k/miles on em. The car itself has less than 78k/mi. and the engine bay was extremely clean when I purchased the car earlier this week. The day I purchased it, I had the trans. fluid changed as well as an oil change and the air filter replaced. Other than that, I'm assuming everything else is stock. What would you suggest as far as a "tune-up" goes? I would take it to a mechanic locally but, Ive been burned the past 3 times Ive tried that " I had some jerk put 10w50 in my bmw323 and that cost me $400 in gaskets alone." I'm mechanically inclined enough to do most of the work myself, if I can get enough spare time on a sunny day. None of my check engine lights are on so I'm clueless as to what to do. Ya think there could be some trash stuck in a valve or something? Thanks

 

[Protege52003]

well, if you have old wires that have cracks and it is rainning; that could cause a rough running engine when the wires get wet. plugs get mis-gapped and should get changed at 30K if not earlier (they are cheap, too).

look at the air-filter and make sure it is a new one. check the EGR valve and clean it. not sure where it is on the 2.5L though. will cause a rough idle when stuck open....

all these are pretty easy to do and don't cost much......

re-set the ECU by disconnecting the battery and pumping the brakes a couple times.....

 

[Sinika74]

Its definately not the wires, they appear to be in very good condition. I'll check the plugs as soon as the rain stops. I just eyeballed the airfilter and its definately new..."btw, do you have any experience with K&N filters?" I'll definately check the EGR valve.."thats uhh, engine gas recycle..right?" If you have any tips on what to use to clean it and how to clean it, I'd love to hear em. This will be my first attempt at an EGR cleaning, but Ive been wanting to learn how to do these types of things for a while. Ive been suspicious about the ecu myself. Pumping the braks?...really? Whats that do? Do you know of any good aftermarket ecu units that dont cost an arm and a leg? Hey, thanks again for responding...I really appreciate it

 

[Protege52003]

egr: Exhaust Gas Recirculating Valve Link,

http://www.misterfixit.com/egrvalve.htm

-R

 

[Nutari]

93-97 626's had really really bad trannys. around 70k miles, they pretty much just die.. and you will need to buy a new one.

google '95 mazda 626 OD light flashing'

 

[Shane5425]

93-97 626's had really really bad trannys. around 70k miles, they pretty much just die.. and you will need to buy a new one.

google '95 mazda 626 OD light flashing'

its only the 2.0 4cyl. that has the tranny problem.. that was a badly designed tranny, i have changed a few.. amazing how ford cant design s***.. the v6 version was a mazda genuine tranny, hence no probelms..

 

[Sinika74]

Ok, the rain is letting up so I'm getting ready to re-set the ecu, clean the egr valve and check the plugs. Thanks again for all the help and I will be back with results

 

[Nutari]

its only the 2.0 4cyl. that has the tranny problem.. that was a badly designed tranny, i have changed a few.. amazing how ford cant design s***.. the v6 version was a mazda genuine tranny, hence no probelms..

oh ok..
lucky then.


my gf's 626 just died recently..

trying to find a new engine for it.

 

[Shane5425]

the onlything good for our engines are ngk plugs.. that is mazdas factory brand..

 

[Sinika74]

Ok, I checked the egr valve and it was a little nasty but I cleaned it. I changed the plugs "the previous owner had Champion RC12MC4 plugs in it" and installed new NGK ZFR5F-11's gaped @ .43 The car gained a bit of throttle response as well as a little power but it still has the above stated problems. I also noticed that all but 1 of the 6 plugs had white crud baked on to the tips.."running lean?" The 6th plug.."which was on the #5 cylinder" was just the opposite, its tip was completely covered in oil. As a matter of fact, everything below the threads on the plug was covered in oil. Anyone have any ideas?