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Discussion Starter · #1 ·
hey all this is my first lt1 engine and it has a slight problem. i just purchased the car and it was there when i got it. when it idles or you give it gas drivin all is god but when you are cruising around 60mph it has a slight miss, sometimes barely there and sometimes a little worse. i changed my plugs and inspected wires and they seem ok. could it be the opti, or maybe just a cap n rotor? i just ask cause befor i start taking the waterpump and all off i want to see if there may be something else im missing.
 

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I would check the egr system giving your cars symptoms.
replacing to the F body egr valve is common.
 

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see the diagnostic helps sticky in this forum.
 

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Discussion Starter · #5 ·
ok so i took the egr off cleaned it up a little checked to make sure it holds vacume and the car still has the very slight miss. im guessing that i will need a new opti
 

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Don't jump straight to the most expensive option. It could be a lot of other, simpler things. You checked the plugs, but what about the plug wires? Have you checked for vacuum leaks? Cleaned the MAF? Checked and changed the PCV valve?
 

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Discussion Starter · #7 ·
Don't jump straight to the most expensive option. It could be a lot of other, simpler things. You checked the plugs, but what about the plug wires? Have you checked for vacuum leaks? Cleaned the MAF? Checked and changed the PCV valve?
plugs are new wires look good. no vacume leaks and its a new maf sensor. i havnt done the pcv valve yet funny thing abotu the maf sensor is the person i bought the car from was not very bright, he changed the maf 3 years ago and still had a check engine light on and couldnt figure it out. when i got the car home i relized he put the maf in backwards and that fixed the cel
 

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I have no clue where you live, but until about a year ago my wife's daily was s 95 SS. She was complaining to me about a miss in the car while going down the interstate. I rode with her and noticed it was the A/C compressor cycling on and off. I could repeat the miss by pushing the A/C button on and off.

If you are not using your A/C I would check the coil wire first then feel and look at the bottom of the water pump to see if it's wet. Next I would swap the coil before messing with the opti. When I go on trips I take a spare coil, coil wire, belt and belt tensioner. I have only been stranded once by a bad Accel coil.
 

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Discussion Starter · #9 ·
i live in fl and yes the miss feels exactly like the a/c kickin on/off, but it still has the miss with the air off. i think im going ot take teh waterpump off tomorow and inspect the cap rotor and everything down there.
 

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Check the easy stuff first before jumping into the opti.
 

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Leave the opti for last. If you have no idea how old are spark plug wires, just replace them. It doesn't matter if they "look good". I had similar problem and and everything "looked" good. Even some professionals told me that there is no problem with spark plug wires. But I knew those wires had almost 100 000 miles and I replaced them anyway. Guess what...that fixed the problem :)
 

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I had the same problem starting at 102K. I replaced the opti, water pump, coil, FPR, belt and hoses at the same time. Problem still existed. Got irritated and took it in for diagnostics. Claimed wires, spent $400 on wires and leaking pinion seal. Problem still existed. Got really irritated and took it to the chevy dealer. Bad spark plug on 4 and 8 (oil fouled) which were replaced within 15K miles of the other work. They cleaned the plugs and put them back in. Got it home and threw another set of plugs in it. Problem went away. So where's the oil getting into it, no smoke out the exhaust? Then came the knocking and pinging which kinda went away with super unleaded. Car still lacked power and would knock on occasion. I had done the egr valve and solenoid at about 70K when I got the CEL light and pulled the codes so I ruled that out. The last thing had to be either the intake manifold gasket or the O2 sensors. Did the intake manifold gasket last weekend and the problem is finally gone.

I look at it this way. The car got a complete tune up and is ready now for another 100K. I bought it 5 years ago for $6995 with 14K in perfect condition. I figure I've spent roughly $1300 on it not including tire, filter and oil changes which is much better than making car payment. Just wish I could find a silver hood to fix the whoops my wife did with her suburban.
 

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Look for burned wires against the exhaust pipes, particularly the O2 sensors and the water temp sensor in the passenger side head. Also check for exhaust leaks.

Check the ground straps. These fuel injection motors are very sensitive to bad grounds.
 

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Discussion Starter · #14 ·
well im gona have the plug wires changed. id do it myself but it looks like a bitch. the car does have a very very small exhaust leak when its cold you can barely hear it could the be the problem?
 

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well im gona have the plug wires changed. id do it myself but it looks like a bitch. the car does have a very very small exhaust leak when its cold you can barely hear it could the be the problem?
That sounds like a broken bolt on the exhaust manifold. If it goes away after warming up it is resealing. My SS has the same problem but keeps leaking after it's warmed up and it has no miss. I'll fix it later with headers.
 

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Discussion Starter · #16 ·
ok here is a update im screwed lol.... actually the 2 rear bolts on the drivers side exhaust mani are broke off in the head. so obviosluy that is where my exhaust leak is coming from, could that have anythign to do with the miss the car has? and also any tiips to drill out those bolts?
 

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It possibly could lead to burnt valves but I don't think the miss is caused from that. You might be better off paying for some diagnostics and then fixing it yourself. I should have done it that way but I'm stubborn.

I'll leave the bolts to someone else as that is beyond me. I'd probably outsource that one.
 

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the leak will cause the o2 to either lean/compensate, the ecu will go into the close loop and you will have a miss or other issues like a stumble hesitation, surging ect...


fix this first. do not touch anything else until this is resolved.


OR

i can mail you a turd in a box and you can sit there and toss ur money at that.

thanks
wolf
 

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Discussion Starter · #19 ·
the leak will cause the o2 to either lean/compensate, the ecu will go into the close loop and you will have a miss or other issues like a stumble hesitation, surging ect...


fix this first. do not touch anything else until this is resolved.


OR

i can mail you a turd in a box and you can sit there and toss ur money at that.

thanks
wolf
of course im going to fix this first, but the leak is not bad at all, it is not putting a cel on and the leak actually clears itself up after abotu 45 second when the mani gets hot. i will be fixing this this weekend anyway.
 
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