Hesitation problem

[Black Stampede]

Hey guys, im posting this in year because Im sure you guys know more than the 4 banger crowd. Anyways, I just purchased an '89 fox beater 4 banger and on the drive home it was hesitating at lower RPMs really bad. I got it home changed the plugs and the oil and filled the gas tank. Drove it the next day and it drove great........for about 5 minutes. Now its doing it again really really bad and its to the point where I have to pretty much mat it to get through the hesitation. What is this things problem? Any help would be greatly appreciated. Thanks. Btw, the thing costed me 300 bucks so its not like I got ripped off or anything.

 

[HISSIN50]

Any codes? The 4 bangers use dual ignition, dont they (8 plugs)?

Good luck.

 

[Black Stampede]

I still gotta scan for codes. Does fuel filter come up on codes if its bad?

 

[HISSIN50]

No there is no code for a fuel filter. You might pop a lean code if it is restrictive enough.

Good luck.

 

[Black Stampede]

alot of people are telling me tfi module. Any input on that? btw, alot of times its ok for the first 5 minutes or so of driving after it has sat overnight.

 

[HISSIN50]

A bad TFI will normally start to fail once the motor gets hot and/or RPM's are higher. The fact that you have the Low RPM burp is a little counterintuitive towards being a TFI (to me). That certainly doesnt mean that isnt the issue.

A bad TFI can toss an ignition/IDM code so look for that while pulling codes (which is still where I would start).

Good luck bud.

 

[wytstang]

Seafoam it, clean the TB & maf ....unplug the IAC and see if it dies. Good luck

 

[Black Stampede]

Thanks for all the input guys. Sorry to hound you with questions but what do you think about it being the thermostat? It has a brand new heater core and the heat does not work so i bought a new stat that i havent put it yet. One of my buddies thinks that stat my possibly be the cause of it having trouble down low. I dont exactly remember what he said but it was something about the motor not being able to get up to temp and it not getting into the right loop. Does this make any sense?
And on top of that like i said, when you first start driving it after it has sat awhile it is ok for the first 5 minutes or so.

 

[wytstang]

I've seen/driven a 98 gt run like crap because the tstat was to cold. But it would run fine up until 4g's then it would hit a brick wall almost like a miss(sp?) under load. It's possible but the obd1 isn't as picky as the obd2. Tstats are cheap and it's possible it could be running rich due to the motor/cpu wanting to reach operating temps.

 

[HISSIN50]

I still would not be guessing and would be pulling codes. The computer is complex, but its self-diagnostics help us to help it.

There are so many things that it could be - sensoriy input, bad plug wires, etc etc. It is gonna be hard to make edumacated guesses IMHO.

Good luck.