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15yearsaturnguy
15yearsaturnguy, Saturn master tech
Category: Saturn
Satisfied Customers: 1918
Experience:  25 years automotive experience, 15 years with Saturn
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99 Saturn: upon acceleration..a hill I have very little power..jerk

Customer Question

I have a '99 Saturn Sl and I am having problems with a lack of power upon acceleration. Going up a hill I have very little power. I also noticed that as I accelerate the car will jerk.Once I get moving I am fine. It is only when I accelerate that I notice that I have very little power. I just had the EGR valve replaced because my mechanic thought that would help me out.But, I still am having problems. My mechanic mentioned that I might need a valve job done. I know nothing about cars so any help will be appreciated. Thanks
Submitted: 6 years ago.
Category: Saturn
Expert:  15yearsaturnguy replied 6 years ago.

15yearsaturnguy :

Hello and thank you for your post. I am a master certified GM tech, with 15 years Saturn experience,and can help you to resolve your issue.

15yearsaturnguy :

is the engine misfiring? (shaking or stuttering on accel?)

15yearsaturnguy :

can you duplicate the hesitation when in drive and hitting the gas and brake at the same time?(power braking)

15yearsaturnguy :

does the service engine soon light ever come on and have you had this scanned for codes?

Customer:

No,the engine is not misfiring. The service engine light came on once a long time ago but has not been on for a long time.

Customer:

Sorry for the delay to respond but I had to leave for a while.

15yearsaturnguy :

OK the problem with diagnosing a hesitation without a code to start with is that we need to do a lot of testing to try to figure out why it runs so bad. I can't just point and say you need a blank or a blank.

15yearsaturnguy :

so, what I would start by doing is checking the orientation of the spark plug wires on the coils.

15yearsaturnguy :

the cylinders are numbered 1-2-3-4 from left to right (when facing the engine) and on the coils they must be 4-1-2-3.

15yearsaturnguy :

if 4 & 1 are reversed, bad things will happen.

15yearsaturnguy :

second, unplug the coolant temp sensor and see if it has wetness or corrosion in the connector. That would indicate a cracked sensor.

15yearsaturnguy :

then if that is OK, take a fuel sample. Dirty fuel or fuel with water in it will cause this as well.

15yearsaturnguy :

then if all that is ok, take a fuel pressure reading. It should be at a minimum 36PSI on this engine when at idle.

15yearsaturnguy :

if all that seems ok, you need to take a compression reading, compare the numbers and they should all be above 125 psi

15yearsaturnguy :

Take a fuel volume test, you could have sufficient fuel pressure but insufficient fuel flow.

15yearsaturnguy :

You may want to just replace the fuel filter as a matter of course

15yearsaturnguy :

If all these basic tests do not lead to a cause, a scan tool will be needed to look at things like fuel trim, map sensor voltage, coolant and intake air temp etc... to try to determine the cause.

15yearsaturnguy :

unfortunately, a hesitation can be caused by a slew of things so I can't just diagnose it without all this info.

15yearsaturnguy :

I hope this helps.