Hi guys,
i bought a 1991 caprice recently. Everything is ok except that when i reach around 40 mph my car stops accelarating at the same rate and continues at the same speed. But if i push the gas pedal to the max then it picks up speed quite slowly. Can you please tell me what is the problem
thank you

 

You have a 305 kinda problem..... Just kidding, but we need a bit more info than what you gave us. You stated a temp problem as well, might be connected. Give us some more info..... numbers, specific temps, that kind of thing.

Mike

 

Suppose i start driving the first two shifts are smooth then when it reaches at 50 mph to be exact then it does not matter how deep i press the accelarator. If i press it half way or almost full there is no difference in accelaration.
Thanks for helping

 

This could be a lot of different things. How many miles are on the car? Was it well takin' care of? how long have you owned it? Do you know the cars history?
I'll need to know the answers to these questions to better help you. I don't know your abilities or experience, so don't be offended if I start with basic questions.

Check this stuff, and if you don't know the status of the parts, or when it was last changed, it might be time for some basic maintenance.

-Trans fluid level good? No bad burned smell? Nice red color?
-Air filter dirty?
-Fuel filter dirty?
-Plugs, wires, cap, and rotor good?
-Exhaust.... converter plugged? Dented, crushed pipes or muffler?
-Flat tires? JK.... sort of.

 

200OZ that's exactly what I would check first too!

 

i have little experience. i had a 86 caprice before this.
- trans level is good. it is pinkish. it smells funny i don't think burned.
- air filter was quite dirty got it cleaned . will replace it if you recommend
- i still need to check the fuel filter
- plugs,wires appear good. have to check the rotor. but sometimes when i apply the brake there is a squealing sound.
- i do not know about the catalytic converter. but the previous owner has installed a borla exhaust. it is under the passenger side.the pipe coming out of the exhaust to the back end is new and a bit thinner i think. also there seems to be a leak somewhere in the front.
thanks again for help

 

The filters are relatively cheap, and easy to replace, so without seeing them for myself I would just replace the stuff, that way there is no question. You may have to get the compression checked if all else checks out fine, the 305 is no power house, but it should at least accelerate a little bit. The '91-'92 305s had issues with the oil returns pluging up if the oil wasn't changed frequently, leading to oil starvation, and increased engine wear.

As with any web mechanics, take our opinions with a grain of salt, have a competent mechanic look at it first to diagnose the issue before throwing money at it because I/we said so.

Mike

 

Ok. thank you very much for helping

 

Just a wild guess , throttle position sensor ?

Low fuel pressure ( fuel filter is under the back side of the car , forward of the rear axel , passenger side , if I recall ?

Weak fuel pump ( had to change mine ) .

Did you say how many miles on the car / engine ?

Is the exhaust blowing strong ?

You do not have a red shop rag stuck in the " tubeing " bring cold air to the air filter ?

I once had a muffler shop check to see if the cat converter was stopped up . He put the car on the lift , took a torch and burned a small hole in the exhaust pipe ahead and behing the cat converter .

Then he had me gun the engine . Approximatly the same amout of exhaust coming out both holes . Cat converter was not stopped up . He then welded the holes back up . Did not even charge me for anything . :-)

God bless
Wyr

 

I would definitely check fuel pressure first make sure it is at the required pressure for that car, then if fuel pressure is low I would change fuel filter, check pressure again, if its low again I would then go to the voltage test at fuel pump connections at tank if power is at required voltage change fuel tank pump it should be easy this will be your second one you are becoming a pro! hope this helps