91 gsx bucking and hesitating

[mtchll50]

i am looking at a 91 gsx in trade for one of my mustangs the car starts up and idles good but after it warms up and you start driving it it bucks extremly hard. while it is bucking the abs light and the check engine light flash on and off together, a relay behind the radio clicks at the same time as well. but than driving back to the guys house it smoothed out for about 2 minutes the abs light and check engine light didnt flash once and every now and than the temp gauge would fluctuate with the bucking. the car was idling and i noticed the tps sensor plug was partialy broke and just set on there so i pulled it off and no change i brought it to probably 2k rpms and pulled it off again and still no change so it is probably a bad tps sensor right? any other ideas would be great because i am trying to decide if i wanna trade for this car or not

 

[spoonman]

Could also be a bad isc motor, you can check to see if it is working with a repair manual, all you need is a multimeter. The abs flashing on and off is weird though i do not know what that is about.

 

[mtchll50]

that is a thouhgt i didnt think about the isc motor.. the abs light and the relay clicking are strange to me as well. i am leaning toward it being a electrical problem maybe a loose plug on a ecu or a bad chassis ground along with the tps and isc possibly. just trying to decide f i should trade or not

 

[viprez586]

check the battery cables for being loose or having corrosion on them. This could cause the clicking you hear of. If they're good then its possible the ECU caps are bad, get down by the center console and see if it smells like raw seafood, if you cant smell it take the ecu out, and look at the board. Its not a hard job to replace them, i did it in 30 minutes taking my time. Get your caps from one of the website vendors, soldering iron, and rubbing alcohol.
otherwise it could be a potential boost leak.

btw: When my car actually runs good, i walk on 5.0 stangs, trade it if youd like a project car!

 

[mtchll50]

i will have to check that out i was thinking it may be the ecu for a little while except the bucking wasnt consistent there was about 1-2 minutes it drove great it is more like a loose connecton

the problem is he doesnt want my 5.0 he wants my limited production 84 svo 2.3 turbo mustang that will walk all over my 5.0 as well

 

[HaveSomeJoe]

You know, I actually had the same exact problems when I had a few big boost leaks, so bad that they were vacuum leaks too, it made my dash lights flash because it was practically stalling and you know how when you turn the key to accessories those dash lights turn on. you knowwww...

try a boost leak test

 

[mtchll50]

i am personally thinking it is a bad chassis groung from the battery to the body how many grounding points do the 91 gsx's have? does anyone know

 

[BUCK]

My guess is an ECU getting ready to "check out" for GOOD - If your lucky it's just a loose Clamp on the pressurized side post-Turbo - But if the price is right, grab it~! - Good luck

 

[mtchll50]

ok i traded for the gsx and i got the bucking part fixed the positive terminal was loose on the battery and a few ground wires where loose.. but i still have a little bit of a hesitation every now an than i can feel it almost cycling in and out.. i can tell when it will start though becuse my temp gauge starts twitching and going from cold to norm so which sensor would be causing this? also what would you rec for plugs and wires

 

[viprez586]

look under the radiator pressure cap, there is a housing with 3 sensors on it, make sure they're all connected and such. As for plugs go with ngks BPR6ES 7131 i believe is the stocking number, for some reason dsms love the cheap plug, gap it at .28 or .30 which ever has the best results

 

[mtchll50]

ok i pulled the plugs and they are ngk 6es's i gapped them to .30 it smoothed out a little bit but my hesitation is still there mainly under 3k rpm and when hit full boost i am leaning towards a boost leak i just have to get the stuff to make a press tester