Help! extreme power loss [Update: consistantly LOW compression]
Update:
I did a compression check on the front 4 cylinders and found them to be between 75 and 85 PSI. I didn't do the back 4 because I ran out of daylight and they are too hard to get to. I know the guage is correct because I did a check on 1 cylinder of my 4.6 Cougar and it read a normal 180.
Is there is a possibility my timing chain could have slipped, therefore not opening and closing the valves at the right time. Hopefully, I'll have access to a timing gun this weekend.
Other than that what else might cause the compression to be consistantly this low across multiple cylinders?
Also, although my check engine light never came on, I did a code check and found 2 things:
1. EVP/EGR sensor voltage below closed limit
2. Thermactor air system inoperative (44)
To my knowledge these don't affect compression.
Original post:
I have an '88 351W with a C6, 33 inch tires.
The thing is a complete dog. On the highway it takes me about 30 seconds to get up to 60 mph (actual speed, not speedometer speed). At 60, the tach reads about 2300 floored and will not rev higher unless I go slightly downhill.....then it will do about 3000 rpm and 70 mph.
My friend says it is due to the 33 inch tires with a stock 3.55 rear. I disagree.
Here is what I have done to the truck since buying it:
- new spark plugs
- new plug wires
- replaced fuel filter
- replaced solinoid
- fixed bad ground
- replaced battery
- replaced exhaust manifold gaskets, upper intake gasket, valve cover gaskets
- had exhaust leaks fixed
- had 2 stage cats replaced with 1 cat
What could possibly be causing my extreme power loss?
The engine runs smooth and seems to run normal....it just doesn't have any power (and gets around 6 mpg in city).
Would testing the fuel injectors pressure per Chiltons be a good first step? I don't have much experience working on engines.
Update:
I did a compression check on the front 4 cylinders and found them to be between 75 and 85 PSI. I didn't do the back 4 because I ran out of daylight and they are too hard to get to. I know the guage is correct because I did a check on 1 cylinder of my 4.6 Cougar and it read a normal 180.
Is there is a possibility my timing chain could have slipped, therefore not opening and closing the valves at the right time. Hopefully, I'll have access to a timing gun this weekend.
Other than that what else might cause the compression to be consistantly this low across multiple cylinders?
Also, although my check engine light never came on, I did a code check and found 2 things:
1. EVP/EGR sensor voltage below closed limit
2. Thermactor air system inoperative (44)
To my knowledge these don't affect compression.
Original post:
I have an '88 351W with a C6, 33 inch tires.
The thing is a complete dog. On the highway it takes me about 30 seconds to get up to 60 mph (actual speed, not speedometer speed). At 60, the tach reads about 2300 floored and will not rev higher unless I go slightly downhill.....then it will do about 3000 rpm and 70 mph.
My friend says it is due to the 33 inch tires with a stock 3.55 rear. I disagree.
Here is what I have done to the truck since buying it:
- new spark plugs
- new plug wires
- replaced fuel filter
- replaced solinoid
- fixed bad ground
- replaced battery
- replaced exhaust manifold gaskets, upper intake gasket, valve cover gaskets
- had exhaust leaks fixed
- had 2 stage cats replaced with 1 cat
What could possibly be causing my extreme power loss?
The engine runs smooth and seems to run normal....it just doesn't have any power (and gets around 6 mpg in city).
Would testing the fuel injectors pressure per Chiltons be a good first step? I don't have much experience working on engines.
