I have an 87 TII, no mufflers but stock exhaust. I find under boost it misses and surges pretty badly, just like its blowing out spark however the plugs are pretty new, wires are new. I am running stock boost with 94 octane, everything else stock.

I am not really sure where to go as i have done a full tune-up and the problem still occurs.

If anyone could help i would appreciate it

thanks
brandon

 

make sure you do not have any vacuum leaks in the system and that the intake hose to the throttle body is tight and do not have any cracks/tears in it as well as the IC hoses.

if that does not help or nothing is found then clean your negative battery terminal end and post and be sure it is nice and snug. remove and clean your negative ground wire where it bolts to the starter and clean the spot where it bolts to the starter. try this and see if it helps, if not then you may have to clean the ECU grounding wire on the top of the rear rotor housing.

if none of those help then you may be having fuel pressure/flow problems, dirty injectors or a semi plugged up fuel filter can cause this as well.

 

Start your car up in the dark, pop the hood and bring your rpms up. Look for 'leaking' spark, starting with the coils, working down to the plugs. Friend of mine had the same problem above 5k rpms, he had a crack in the coil tower where the spark plug wire boot connected.

 

Same here. I cured a full-load miss by replacing one spark plug wire.

 

maybe your wastegate is malfunctioning, and hitting boost-fuel cut. what is the reading on the boost gauge? what kind of plugs do you have? best be ngk. i tried autolites in my old 12a and they had a slight misfire under high load, i used the plugs for less than 60 miles only to get the car running.

 

If your wires and plugs are good, it sounds like it could be the crank angle sensor. Check that, if you have a friend with a turbo II just pull his, swap them real quick and see if it works then.

 

I found it... I changed the vacume line from the im to boost sensor and neglected to re-install the little restrictor in the new line... i just used a bleeder valve and its all cool now

It Has developed a very severe case of the 3800 rpm hesitation tho, so i gotta check that out

thanks
brandon