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Ask Amedee Your Own Question
Amedee, Former ASE Master Tech
Category: Car
Satisfied Customers: 26621
Experience:  ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
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97 geo metro 1.3 I4 engine. My car stalls when accelerating

Customer Question

97 geo metro 1.3 I4 engine.
My car stalls when accelerating normal or quickly from stop or slow down. If I accelerate very slowly it works.
After it gets over the hump it speeds up great.
I put it in neutral and messed with it a bit. I found that if I slam the gas pedal then it works pretty well... Under no load... But when I push it quickly over and over it stalls. This car has a map sensor, but no maf sensor. I suspected it might be something to do with those? Amy ideas?
Submitted: 1 year ago.
Category: Car
Expert:  Amedee replied 1 year ago.

Hello and welcome!

My name isCustomerand I can assist you with your question.

Expert:  Amedee replied 1 year ago.

Is the check engine light on? Are there any codes?

Expert:  Amedee replied 1 year ago.

Do you know what the engine vacuum is at when the engine is at idle?

Customer: replied 1 year ago.
The codes were not cleared by the old owner. I just bought it.They replaced the fuel pump, distributor cap, plugs, injector, and evap canistor.Since I first posted I have replaced the cracked exhaust manifold, plug wires, and the rotor in the distributor.I did some testing on the ICS and the idle motor moves back and forth. There appears to be spark and combustion in all cylinders. The tps sensor resistances tested out fine. Although when I tried to calibrate it using continuity on pin 3 and 4 I get low resistance readings, but no beep from my meter. I did a compression test with the car off. I ran the fuel dry, but I forgot to put the throttle open. The result was 150 on all 4 cylinders.When I did the test I found that the newer plugs were completly fouled with oil. I cleaned them, and gapped them. I have some new ones, but I didn't want to ruin them yet.I think it needs new valve seal and maybe new valves, but I am not sure this would cause the stalling.I will check the vacuum, but I already went over it with an ultrasonic test tool. I didn't find a leak. I might have missed it though.That's all I can think of right now.What do you think?
Expert:  Amedee replied 1 year ago.

Hello and thank you for that information.

When I was asking about vacuum reading, I would not talking about checking for vacuum leaks. I was talking about checking engine vacuum to see how well the engine is breathing. This is very important.

We need to watch the oxygen sensor reading under a load when the engine stalls or bogs down under a load. This will tell us if the engine is starving for fuel.. which I suspect it is.

Also, have you checked for plugged exhaust?

Customer: replied 1 year ago.
I tested the car while the exhaust manifold was removed. It had the same problem.
Expert:  Amedee replied 1 year ago.

Ok, good! That takes care of the restricted exhaust theory.