Help me trouble shoot my problem

**friendsofdonr** · 12-21-12, 0:02

So this problem is intermittent and it only seems to happen under a load. Doesn't seem to happen when I rev the engine.
ON idle the rpms will raise under turning on my high beams to 3k
or just sitting it will rev up and sometimes will settle around 1.5kor 2k
When cruising it feels like it misses here or ther but it isnot reflected in the rpm gauge.
It appeared to only happen at less than 1/2 tank of gas but does not occur when over 1/2 tank.

Problem test 1 - YouTube
Test video 2 - YouTube
Test video 3 - YouTube

the second video shows how violent the stutter can be... please pardon my loose interior rattles and rap music on the second and third videos.
I was gonna do a cam swap and egr block off, but feel its a little more important to fix this before i go adding complications.

the car is a 93 2.0l mtx with the upgrades in my signature. I have redone the passenger side motor mount ground and drivers side motor mount grounds. I have a battery relocation in the trunk with decent ground as well.

I was gonna do a fuel pump hoping that would "solve" my problem. Fuel filter, cap, rotor, wires and plugs all have less than 10k miles.

**friendsofdonr** · 12-21-12, 0:42

And for reference, when I ssy and notjing its like there was absolutely no power at full throttle to accelerate.... like I was towing a boat or had 800lbs inside the car....

**friendsofdonr** · 12-21-12, 16:05

I pulled the vacuum line off of the egr valve plugged up both ends. I don't have all the parts to do a block off properly and now. now the car does not jump to 3k when I have my defrost on and turn on my high beams. I also put in a bottle of lucas fuel injector cleaner and a half tank of gas. we'll see if between the two if it runs better and doent get any problems. my thought behind pulling the vacuum line is that the egr valve wont actuate. I got a 93 so I don't believe id throw cel codes if it was going out.

**friendsofdonr** · 12-21-12, 18:42

Now my idle pulsates when coasting from 1k to 1.5k...

**djdevon3** · 12-21-12, 22:25

Here's a list of possible suspects to look into according to the WSM.
1. MAF (poor connection or wiring) If possible clean it. Dunno about the MTX MAF but the ATX MAF is easily cleanable.
2. IAT (poor connection or wiring)
3. Distributor (damaged cap or rotor)
4. Fuel Injector (shorted to ground)
5. Fuel Filter (clogged)
6. Air Filter (clogged)
7. Catalytic Converter (clogged)

I've also heard of people having a similar issue (if not exact) simply due to bad gasoline. Purchase your next tank from a different brand and/or gas station.

**friendsofdonr** · 12-21-12, 22:35

Thanks. I have no cat. I have tried different gas stations and I just cleaned my air filter. I will check the wiring for iat and maf. Im gonna go ahead and swap injectors and fpr as well. Can I just spray the maf to clean it?

I will also pull the cap and rotor to inspect those. The filter has less than 10k miles. It shouldnt have clogged that quickly. But I really hope the ditsy isnt on its way out.

**97mx6** · 12-22-12, 12:02

Quote:

Originally Posted by friendsofdonr

It appeared to only happen at less than 1/2 tank of gas but does not occur when over 1/2 tank.

^does this still hold true?

its hard for anyone on here to say whats wrong. you have to start actually changing things.

ide take a few hours and do the fuel pump first.
even if it doesnt solve the problem its good to do and itll point you in the direction of the problem

**friendsofdonr** · 12-22-12, 12:14

Yes... its still true. Im at a loss but im gonna chage the few things I have extras of just to make sure its not those. The thing that is the most bothersome is this is intermittent. Which leads me to think its not spark related. I probably wont be able to do much work or troubleshoot until after Christmas.

**friendsofdonr** · 12-22-12, 12:14

And thanks everyone for the help so far...

**djdevon3** · 12-25-12, 13:22

I have a video on MAF cleaning. Search Mazda 626 MAF cleaning on YouTube. I think the Manual has a different MAF but might be cleaned the same way. Hope this helps.

Mazda 626 - MAF Cleaning - YouTube

**friendsofdonr** · 12-28-12, 19:27

Checked my plugs...

Help me trouble shoot my problem-uploadfromtaptalk1356744168374.jpg

They all look like this. Looks like a good burn pattern to me. Im gonna try and clean the maf on monday and make sure all my vac lines arr sealed from the egr delete. Gonna also order an afpr and walboro soon if not monday. The car still only acts up and stutters when the tank is less then half and after its been ran a while to operating temperature.

Below half a tank and near a 1/4 tank I recieved two harf starts where it sputtered around 250rpm and when I gave it gas it started to run better and returned to normal idle.

natev8 · 12-31-12, 20:32

MAF won't always through a CEL. I would clean your MAF first. Just to rule it out I would also run a test on your TP Sensor. I've seen cars stutter and have throttle issues similar to yours with failing TP Sensors. If you can run a fuel pressure test that would help also.

**friendsofdonr** · 12-31-12, 20:44

would an afpr tell me if my fuel pressure is lacking? or would it help me diagnose at all? I can get a can of maf cleaner wednesday morning.

natev8 · 12-31-12, 20:51

As long as it has a fuel pressure gauge on it. My aeromotive FPR has a gauge threaded into the side of it that shows the fuel pressure.

**friendsofdonr** · 1-2-13, 13:51

Cleaned the maf..... no success there.

Its officially started dying on me wont hold a steady idle on occassion. When it does hold its either 1.5k or 750rpm.

When it dies it tries to hold at 250rom then dies. Both times its resulted in a crank but no go. After holding and pumping the gas pedal it finally goes after a while of pumping and cranking (thats what she said)....