My Mazda has a bad hesitation

[Tri-ZNate]

ok the basics------ 1993 Mazda B2200 (carburated) stock everything except plugs, plug wires, air filter, and distributor cap.

Now the tricky part. There is only one spot in the RPM range where it hesitates (2500 when cold 3000 when warmed up). Now it will only do this WHEN IN GEAR. If I have it in nuetral and rev it there will be no studder/sputter/hesistion but if I put it into gear and bring it up into the RPMs it will act up. Also I can just push the throttle down and it wont be hardly noticable. (also the hesitation isnt like a nice little bog it is very violent like when you leave your vehicle in gear and let it get down to like 600 RPMs.)

So far i have been told it could be the accelerator pump or it might not be advancing the timing. Any Ideas?

[200xman]

Check all your vacum lines for cracks or leaks. I'd also try replacing your fuel filter.

[brapp]

drive it off a cliff and buy m7y chevy lol or quit riunning biodiesel in a gas motor.

[Mike_Ham_250R]

drive it off a cliff and buy m7y chevy lol or quit riunning biodiesel in a gas motor.

LMAO!

Maybe you have to rejet HAHAHHA.

[Tri-ZNate]

hey josh you hook me up with a cheap diesel truck and I'll drive it off a cliff

[firehart]

How many miles does it have? It could be a bad cap or maybe a worn distributor.

[Tri-ZNate]

just rolled over 101,000 miles.

[PowerTrike]

Have you cleaned the carb recently? I would atleast try running some SeaFoam or something through the gas... My friends old carburated accord had the same problem and it turned out to be a vaccum leak around the carb or intake... it did have a very slight hesitation in neutral tho, however much more detectable when in gear. Exhaust seem blocked at all? I'm assuming you changed the rotor when you did the cap?

[Yamaha Tri-Moto]

What do you expect? it is a Mazda.

[Tri-ZNate]

What do you expect? it is a Mazda.

Yeah yeah yeah, I guess i could have gotten a F150 or something and got a decent 15mpg but got greedy and wanted 26mpg

Powertrike there is only one loose hose and it runs from the exhaust manifold to the air intake? Thats how it goes but I dont understand WTF its supposed to accomplish. I dont suppose if I sprayed carb cleaner around the carb it would show a leak like spraying it around the intake on an ATV right?

I'll try some seafoam since there is alot of linkages I have to take apart to open the carb up.

[hambone]

be careful spraying the cleaner. many a car has been burnt up by checking for leaks with carb cleaner.
i'd use WD-40 it's safer and will have the same effect.
the vacumn line going to the exhaust proably goes to the egr valve.
if it's completely unhooked plug the line and test drive it.
another thing to check is the fuel filter.
you should have one on the the engine and could have one located on the frame under the truck.
hope this helps?

[Tri-ZNate]

yeah the line is hooked up but its loose so i should probably tighten it up, and I'll be sure to check the filter. thanks

[Chevy200s]

I had a truck that had a very similar sounding problem. My 87 chevy blazer was throttle body fuel injection so it was a little different, but still similar. When the truck was in gear, it would sputter at a certain rpm range, before and after that "spot" it was fine, and in nuetral it was also fine. It ended up being the EGR valve. Not knowing anything at all about mazda's, I dont even know if they have an egr valve, still worth looking into though.

Its easy to test too, just find it (its a round diaphram that you can put your fingers under and reach up push the valve), push the valve, if it either doesnt move, is very hard to move, sticks, or doesnt come back down at the same speed it went up, your egr valve is probably bad. You can either replace it which is an easy fix, or you can jimmy rig it If you cap off the vacuum line going into the egr with a machine bolt, it will force the computer to use a preset value, and it wont use the egr. It will fire the check engine light every once in a while though. i recommend the first method, but I have seen the second work just as well, lol.

If there is no egr or that doesnt take care of the problem, try checking the distributor like mentioned. Sometimes they get worn at the bottom, a good way to check is to very gently push and pull at the top, see if it moves at all or if there is any play, if there is that will mess up your timing. other than that check the vacuum lines for leaks.

If none of those things work, sell the truck and buy a chevy good luck man

[Tri-ZNate]

yes there is indeed an EGR valve so i'll check that hopefully today when i get a chance. And we are actually looking a 3500 chevy diesel so maybe the mazda is gonna end up going bye bye anyway.

[Chevy200s]

chevy diesel would be pretty cool, is it a 6.2, 6.5, duramax, etc? If you get it post up some pics!