Here's a question for all of you:
86 GXL
Driving around here and there seems to be fine.
Driving on highway speeds fine.
Driving on highway for over an hour and a half, not so fine.
The thing is when I drive it on the highway for over an hour and a half, upon slight acceleration (usually following slight braking for traffic) it studder, jerks, hesitates, whatever. But it acts as though it will die. Pushing in the clutch and reving it doesn't work. It won't usually get above about 4-5k.

Could it be my alternator going bad? It usually keeps a good charge on the battery, normally around 13 or 14.

Could it be my fuel pump going out? Or perhaps clogs in the fuel system? I replaced my fuel filter, it looked pretty bad, but afterwards it was even worse or atleast didn't help at all.

Maybe my grounding just needs done to the fuel rails, but I don't know that it would make that much difference.

The thing is that when it starts to sputter, I can shut the car off and fire it back up and keep going for another while (anywhere from 10-30 mins) before it does it again.

Any sort of ideas with plausable explanation would be helpful.

Thanks

 

It could be several things. Are you seeing the check engine light coming on? When was the last tuneup where among other things you replaced the fuel filter, air filter, sparkplugs, sparkplug wires, etc..?

My TII did this on the way back from Maryland, but that was because my intake manifold & intake piping behind the MAF (mass airflow sensor) was cracked/warped. So the ECU was supplying the incorrect amount of air and thus the studdering. The check engine lite kept on going on/off.

Could also be grounding. You might want to clean all the engine ground contacts, add an additional engine ground, clean the ECU mounts (passengers side floorboard), etc..

Also might try cleaning the MAF connectors.

If your OEM exhaust has more than 85K miles on it, the cats could be clogged. After a tuneup, your first reliability upgrade is partial exhaust headers to replace your pre-catatytic converter & a new "rated for a rotary engine's heat output" main catalytic converter.

I'm sure there's several other suggestions.

 

its an 86...no check engine light right?

 

There isn't a CEL on the S4's. You can make a engine code checked lamp set for less than 10 dollars. Hook that thing up and check for codes. I have mine installed in the radio area for daily use. It helps when something happens right on the road and it spits a code at you.

 

I have changed my plugs, wires and fuel filter recently. I'll check my air filter. I could by my cats, I guess. Is there any easy way to test the intake manifold for cracks?
Thanks for your suggestions.