Herky Jerky 86 5.0

[Robs86]

Can anyone tell me why my 86 5.0 pony "jerks" from time to time while I'm driving??? It's a 5 speed car and when I take off (normal driving) she bucks /jerks in any gear,even when cruising in 5th gear. Then it will go away,and when it feels like it,it'll start up again and sometimes the car will run great with no problems. I'm not a wrench at all so any help or ideas would be great!
Thanks,
Rob

 

[Wicked One]

Little more info needed please.

What RPM, under throttle, Idle normal.

Sounds like a clogged fuel filter from what you are saying.

 

[Robs86]

IT happens at any rpms.Yes,it happens while accelerating mostly but it also happens while cruising along in 5th gear too! Idling is no problem.....runs fine. Recent work done......new radiator,water pump,hoses thermostat and a new serp. belt. My first though was also a fuel filter or a bad injector or somthing fuel related.Then I was thinking perhaps something electrical.I just don't know......again,I'm not a mechanic but was thinking in terms of logic.

 

[Gingerbreadman]

change your o2 sensors,i had the same problem,,,,also check driveshaft u joint,trans mount, crossmember mounts,pinion bearing,and fuel pressure,and vaccuum hoses,,,,r u still runnin the speed density or did u convert to mass air??

 

[Robs86]

I did not convert to mass air.The car is all original without any mods (as far as I was told.) I did notice my oil gauge was kind of on the low side but it does fluctuate alot....all other gauges read normal.I was told by previous owner not to rely on those gauges much BTW.

 

[1995gt]

i would start with the fuel filter first its cheap (10.99 at advance) and pritty easy

 

[BKD]

injector cleaner....mybe.

 

[Gingerbreadman]

yea the guages are unreliable in the 85 and 86,it will fluctuate with idle the amp guages are junk to,,,id say do your 02 sensors there 35 bucks a piece,get both and no more bucking,those computers rely on the o2 sensor,if it runs good when wide open throttle,your fuel system is fine,it will break up and have a loss of power the higher the rpm if it was a filter clog,u can try the fuel filter but its in the tank and i dought its clogged,the one i pulled out of my tank wasnt bad just dicolored,has 106k on motor when everything was dropped and pulled

 

[1995gt]

purolator f65455 inline fuel filter $11.99 the strainer in the tank is just to grab big stuff but i do agree on the O2 sensors if the car runs fine at WOT. best way to find out is to hook up a pressure gauge and drive it, see what you get if its steady then you've narrowed it down. im pritty sure manufacturer recomends O2's every 100k and fuel filter every 30k so they probibly could both use a changing.

 

[PJB]

Mine does it too and I cant figure out what it is.
It did the same thing with the old motor, old clutch and old U joints and the tranny mount and fuel filter are new too.

Its rather random and happens in any gear.

My car isnt stock anymore and some people say it might be the cam because it seems to happen when its under the 2600-6200 rpm range of the cam.

 

[fred1995]

I had an 84 GT with the 5.0 automatic, and early fuel inj. Throttle body type carb, and had a similar problem. The EGR valve was all plugged up, pulled it off,cleaned it out, made sure it was working, and the problem was cleared.Its was an inexpensive fix.

 

[PJB]

except my egr has been removed and it did the same thing with it hooked up.