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contributions: 3
Help me, please help me,
I will explain this as best as I can so I don't confuse the folks reading this.
This all began several months ago....
I had been losing coolant and having catalyst efficiency codes along with a misfire at idle. So I rented a coolant system pressure tester and fuel system pressure tester. The coolant pressure test failed as I suspected and found that leak on the front of the engine driver's side. (intake manifold gasket)The fuel pressure test passed. Leak down was good. Pressure with engine off was good and pressure while engine running also good. The misfires at that time turned out to be a bad spark plug and wires. Replaced the spark plugs only to find out from a dealer the parts store gave me spark plugs of the wrong heat range. I did install the correct spark plugs after that. Bought a set of Duralast spark plug wires from Auto Zone. (that was a mistake) and replaced the distributor cap and rotor with AC Delco. That fixed the misfire at idle. I purchased the upgraded Felpro intake manifold gaskets and while I was in there also bought a new fuel injection assembly. After removing the intake manifold I found some carbon build up in the intake and intake ports. Not horrible like some pics I've seen but none the less it was there. The "valley" of the engine was clean. Zero sludge build up. Cleaned the carbon out of the intake and intake ports. I knew these problems had damaged the catalytic convertor so I purchased and after market front exhaust system. A Walker brand. That fixed the efficiency codes. Truck ran great for two days. I did all of this back in April and May of this year.
Now I've been having random misfire codes, mass air flow codes, primary side coil codes and the truck just would not pull, especially up inclines and the engine coolant temp will reach 220 plus with the AC off. (It has never done that even with the leaking intake manifold gaskets)In the last month plus, these are the things I have done to try to fix this....
When I changed the spark plugs the first time, I also did a compression check. All cylinders were right around 160 psi and all of the spark plugs were very clean. I have replaced a number of parts but not all are AC Delco parts.
1.Throttle position sensor
2. MAP sensor
3. Idle air control
4. After market MAF sensor. Which was not the problem so I put the OEM one back on.
5. Engine coolant temp sensor
6. New distributor
7. New AC Delco spark plug wires
8. New AC Delco PVC valve
Installing the new distributor helped EMENSLY. Truck pulls way better but not 100% I can pass other vehicles on the highway now. I have searched and searched for vacuum leaks and cannot find any. While driving up inclines, if I keep the rpm's below 2500 I usually won't have misfires (flashing SES light) If I push it more than that the SES light will start flashing and I can feel power loss and the engine temp will start climbing rather quickly.

The PCV valve is noisy because it vibrates terribly. It has never done that before. Why would it do that?
Is it possible to have an internal vacuum leak at the intake ports without having coolant loss?
Should have I used some type of brush on sealant along with the new gaskets where the surfaces of intake manifold and heads mate? G.M. does not call for a sealant used there. If so, what type of sealant?
I hope all of this makes sense and thank you for your time.

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Location: Oregon
what are the codes you are getting now?

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PO894, PO302
PO894 has been ongoing. Dealership installed new remanufactured transmission back in April this year. It has been throwing this code since the day I picked it up. I have taken it back 3 times for this also. They say it's either fixed or there's nothing wrong with it. I have an hour's drive from home to work. At some point after it's at full operating temp it will throw the code. I can see that the torque convertor clutch slipping watching the tach and the 1,2,3 shift becomes very hard and SES light will stay lit.
I know that PO302 means cylinder #2 is misfiring. This is new. As of today, these are the only codes the ECM is showing.

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contributions: 2275
Images: 37
Location: Oregon
well the misfire explains the flashing check engine light. The light flashing means that the problem you are having could cause damage to the catalytic converter. Once the check engine light has come on the vehicle will go into limp mode. that means the computer will keep the car running but it won't work normally. It give you just enough operation so that you can drive it until you can get it fixed. It doesn't want you to keep driving.

If you have documented the trans code from when you had the trans replaced with the reman trans, I'd go back to the dealership that put the trans in and tell them to fix it before your warranty is over. If they don't you should tell them you are going to take it to a tranny shop and it fixed and send them a bill. There shouldn't be any codes. that means there is nothing wrong. A code means exactly the opposite, there's something wrong.

The misfire is what you have to take care of as soon as you can. You're going to have to see if it's a spark problem, a fuel problem or a mechanical problem.

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