93 MX-3 V6 hesitation issue(edited 7/15/12)

[kyser182]

i have a 1993 mx-3 GS v6 5 speed
it has had an engine swap by a previous owner with a K8 from an automatic.
ive cleaned the TB and MAF and replaced the fuel filter.
the engine starts fine. and can be driven pretty normally. until you step on the gas harder then if your driving like a grandma
if i am in 2nd gear at 2000rpm and i punch the gas. All i get is stumble stumble stumble until i let off the gas.
if you learn the gas pedal and EASE into driving you can drive pretty fine. this happens in all gears and all RPM ranges.

(edit)
After taking what you guys have said and figuring out how to get the CEL codes myself here is where we stand.
1long 7 short, 2 long 9 short, 4 long 6 short
17 LHO2S inversion error
29 EGR vent solenoid
46 VRIS #2 solenoid

things i need to know now.
which O2 sensor is that? Front or back?
without knowing what way mazda is looking at the engine. Right half and Left half dont mean squat to me. If anyone knows i would greatly appreciate it!

Ive been playing with the 2 VRIS solenoids on the back of the engine.
the one on the right moves while the engine is cold and i rev the engine up, but stops moving after the engine is warm
If i pull the hose off of it while the engine is running . i hear nothing

The one on the left looks like its .. moving? haha but not in the right direction. it seems to move closed and i start to hear a tick tick tick coming from it until i place my hand on it.
if i pull the hose off of it while the engine is running, you hear air blowing out for a brief moment.

as for the EGR valve. I have not even began with that yet. looks like a new replacement will run at least $170.


Portland has almost no MX-3s in any scrap yards. there is currently one in vancouver,wa and it has basically nothing left

SO. If i must replace the VRIS solenoid. What vehicles are compatable? From what i read i could pull from: MX-6, Millenia, probe, 626?
EGR valve.. any compatable vehicles i could pull from there?
O2 sensors are easily obtainable off of amazon.com. so im not very concerned about that

[Ryan]

Check the connector on the airflow meter, and cracks in the intake tubing.

[mitmaks]

Have you checked if there's any codes?

[kyser182]

I actually do have an intermittent check engine light. it seems to only come on if i am cruising steady on the freeway.
last time the car was in the shop the technician said it came up as "o2 sensor" but didnt say which one
ive replaced the one in the front of the car, but im unsure if the wiring is right because the mulnex plug is gone... and the wires were different color from what the Denso instructions said. had to buy universial since it has no mulnex plug. ive not had the car lifted at home to see the other o2 sensor


I did just go over all the hoses thoughout the engine that i could find. i did not see any hoses cracked/damaged in anyway that i could find. I am unsure exactly what part is the airflow meter(MAF?) but all the wiring and connections look good on that

[mikeinaus]

highway cruise cel is usually in the egr system. o2's can cause stumbling but shouldnt be as bad as your describing. pull the codes and let us know if any come up.

[SuperK]

the O2's shut off when y ou're in higher RPM's. Does the issue persist when you're arounk 4k rev's?

[kyser182]

It does seem to get better at around 4000RPM, get a nice hard pull when the gas is down
but i cant get the engine to want to go past 6000-6300RPM(ish) unless im out of gear. it will but it doesnt seem to like it lol

[mitmaks]

check which codes you're getting.

[kyser182]

I will get them pulled the next time the light comes on. Non commuter vehicle so I don't drive it but 1-2times a week. Work van

[mitmaks]

You can pull codes anytime, you don't have to wait for check engine light to be on. If there's any codes they would be stored in memory.

[kyser182]

good to know. Ill work on getting the codes pulled

[mitmaks]

I'm anxious to see what the problem is as I have pretty much same problem with my mx-3.

[RX8SE3P]

Rockauto.com for your 02 sensors. Denso branded, will plug right up to the MX-3 for $70.

[tbondo]

I too am anxious to know a solution. I have the exact same problem accompanied by a high idle. I was told the stutter may be the distributor?

[kyser182]

My car doesn't have the mulnex plugs for its o2 sensors. Some dip clipped them. And the wire colors don't match the denso instructions. Soooooo yeah
I would love some help with this problem as well hahaha

Wire colors are
1. white/red line
2. Red/blue line
2 wires that are black with red every inch or so..