Surging and bucking under load

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Surging and bucking under load

Post by Sinix3 » Sun Jun 26, 2016 5:31 am

Hey guys. Not sure if im posting in the correct area. Anyways
As of yesterday my 91 na22 5mt swapped wagon started to act rather strange. Under normal driving say im heading down the road it will almost miss like iv just jabbed the throttle. At idle it will surge between 300 and 1000 rpm. Today i swapped out my tps for a ysed one to see if it hwlped and it didnt. Today it was almost like it wanted to stall no matter what but would always catch itself. Its fine when its cold but as soon as it warms up it will surge at idle and buck under load. So far iv tried a different maf that didnt work. While running i disconnected the iac and idle went up? Shouldnt it drop?? XD im thinking i need an iac or a coil only because ot seems to feel like its an ignittion issue almost like its retarding randomly. If anyone has some ideas id love to hear them. Cheers
91 legacy wagon 22 na
93 legacy wagon eg33 swap under way

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Re: Surging and bucking under load

Post by Alphius » Sun Jun 26, 2016 8:36 am

Vacuum leak?

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Re: Surging and bucking under load

Post by Legacy777 » Sat Jul 02, 2016 9:34 pm

Unplugging the IAC will make the idle go up.

With temperature related issues I usually suspect the coolant temp sensor. It's a relatively inexpensive part to replace so I'd maybe suggest that first and see if that makes a difference.
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

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