89 Galant surge at 2250 rpms

[Jtackerman28]

My 89 galant (sohc 4g63) 4 speed auto.

just started having an issue the past few days. It will itemediatly lose power of above 2250 rpm

i.e. driving down the road at 45 mph in 3rd gear and all power is gone. As soon as it gets below about 35 mph (2250 rpms or so) it comes right back on and then will repeat the above for a minute or two. Then be back to normal again.

No check engine lights present.

New parts within 850 miles include (replaced because of no spark that was cleared with a new ignition transistor.)

Coil
Ignition module
Plugs
Wires
Cap
Rotor

I was thinking tps but it checks good. Also ecu is perfect.

Thanks for any help

 

[Lou98GSX]

What happens when you floor it does it run good cause it sounds like a bad o2 sensor . At full throttle the o2 sensor doesn't come into play .You could also have a vacuum leak or air leak after the mass air sensor . .check your air cleaner rubber hose for cracks .

 

[Jtackerman28]

Same thing happens at full throttle. It will hop up to like 4000 (roughly after 2250) then is dead until it gets back below 2250. I unplugged the o2 sensor to put it into open loop and still does the same thing. Maf is a little dirty but has been running good for about 1000 miles like that. New air filter intake tuning is in good shape.

 

[mitsubishikid]

Some ideas that come to mind...

1: test the egr if it turns up good, then pull the egr and clean out it's ports on the intake and the egr with carb cleaner.

2: Clogged catalytic converter or exhaust.

3: vacuum leaks, check all your hoses, gaskets, seals etc.

4: if you touched the mixture screw on the throttle-body you might be adjusted too lean or too rich.

 

[Lou98GSX]

When was the last time you changed your gas filter . You could also have a clogged exhaust . Try dropping your down pipe and see how it runs . also does the engine idle smoothly or is it rough .

 

[Jtackerman28]

Idles smooth I'll try the fuel filter. I have a few new ones laying around.