Just a little background, I have a ‘89 iroc with a 305tpi and 5 speed transmission. My problems are as fallows: During any start up the car will crank over, stall and die. It usually takes a few tries to get it to keep running. When it does idle its very rough, it gets close to stalling and then surges high. The oil pressure gauge oscillates between 50 down to 30 psi. If the pressure drops below 25psi the engine will die.
During driving the oil pressure will read just above 50psi. When I stop or put the clutch in at low speed it dies.
The most serious problem is when driving the car will jerk violently and the ses light will come on and the engine bogs down. The harder you push the gas pedal the more it will bog down. After a few miles the light will go out and the engine will operate normally. All these problems are intermitted and happen regardless of weather, temperature or speed. Plus there are no solid trouble codes that I can read. I’ve replaced the plugs, cap, rotor and fuel filter other than that the engine is bone stock. I would appreciate any advice you could offer.

 

fuel preasure, timing, CTS, TPS, filters would be a few things i looked at

 

Plus MAF sensor...

 

Pull the codes from the computer.Good place to start.

 

Hve you pulled any codes?

When mine was doing that it turned out to be the ignition module. A year later it started doing the same thing, and I ended up having to rebuild the distributor due to a damaged pick-up coil.

 

I changed all the filters and the timing was good. Then I pulled the codes using a paper clip and got a code 34 (maf), but after replacing that and clearing the code nothing else has shown up. I think it has to do with the faults being intermitted and not staying long enough to set a code.
The ignition module and fuel pressure seem like a good next step, thanks

 

When you pulled the plugs, how did they look? Any carbon buildup? Are you sure that the new plugs are gapped correctly? Check out what these other people are saying.

This question is more for those replying, but might it be something with the transmission? Since it's jerking and dying with a little clutch, maybe a probelm lies in there? Granted, I'd check everything else first (codes, sensors, wire connections, etc) before moving on to the tranny. just wondering.

 

Dauntless, The plugs were a grayish color and still serviceable when I changed them. I set the gap to .035 which was the book spec.
I did think about the transmission, but I couldn’t link the symptoms. When it jerks its like the engine is instantly stopped for a split second. Which locks everything up and causes the rear wheels to drag causing violent jerking. When it dies the clutch is in or its out of gear and there is no driving force from the transmission to keep the engine turning.
Does anyone have any thoughts on why the oil pressure would be so high or why it oscillates.

 

Dauntless, The plugs were a grayish color and still serviceable when I changed them. I set the gap to .035 which was the book spec.
I did think about the transmission, but I couldn’t link the symptoms. When it jerks its like the engine is instantly stopped for a split second. Which locks everything up and causes the rear wheels to drag causing violent jerking. When it dies the clutch is in or its out of gear and there is no driving force from the transmission to keep the engine turning.
Does anyone have any thoughts on why the oil pressure would be so high or why it oscillates.

 

i'm wondering if your oil pressure guage and sending unit are operating normally. granted it won't be the cause of the problem, it might help in diagnosing.

although, i'm wondering: is the computer supposed to shut the enging down if oil pressure drops too low? i really have no idea (i don't have a tpi car so i'm not sure how the computer works in one). are you losing any oil anywhere (leak, burning)?

 

It burns about a qt every month and a half, usually in a puff of smoke when being started up after sitting for a few hours. Other than initial start up it doesn’t smoke. I think the valve seals are worn and oil seeps into the cylinders when it sits for awhile. From what I understand the computer is designed to shut down the engine if the oil pressure drops to low.

 

Ok, if that's the case, I'd check that sending unit first. Make sure it's not leaking oil. If it is, replace it. It's not expensive at all. If it's working properly, then my guess would be to check out the oil pump. I can't figure out why the pressure would be oscillating, unless it does that when the pump's going bad. Maybe someone else can back me up on this.