surging while driving down the road

[At1Maverick]

I recently started driving 95 GT (auto) more often and I notice some surging during most driving condition, and during acceleration, I can hear a significant amount of spark knock too. It does have the surging idle issue going on as well. I have dropped the timing down to 10BTDC, I've also tried as much as 14BTDC- which didn't help, so it's back down to 10BTDC.

I've noticed that the dizzy is a little tight when I try to move it around trying to adjust timing. I've cleaned the MAF, checked FP and did plugs and wires, also a coolant temp sensor. No CEL or codes yet.

 

[GT Rob]

I had the same problem I changed everything I could even did the timing and that didn't help so a friend of mine did a compression test and found that I'm down on compression so going to replace my heads and while I'm there going to check my rings. Good luck with your car keep use up to date on what you find on yours. Oh yea mine is a 95 gt automatic also

 

[At1Maverick]

Just got done doing a compression, pretty much got 145psi across the board and I think my lowest was 142(cylinder #2), highest was 148(cylinder #5). Drove with a fuel pressure gauge attached to the windshield and everything seems to be normal as far as fp is concerned.

 

[CC'S95GT]

how old are the plugs, wires, cap, and rotor, and fuel filter? and did you put them on?
And just to make sure, did you set the timing with the spout out?

 

[At1Maverick]

Just did the tune-up myself not a month ago, so plugs, wires cap and rotor, fuel filter are all new. And the PIP is new as well. And yes, I did take the spout out to adjust timing.

 

[CC'S95GT]

Typically idle surge is a vacuum leak

 

[GT Rob]

i thought it was a vacuum also did a compression test and got 125psi all on the driver side but now where thinking it's a stuck valve

 

[At1Maverick]

So did I on mine, I had done a smoke machine test and nothing leaked. There's a noise coming from my CAI that I though was a vacuum leak from inside the fender. I'm about to do a leak down test to see if it's a valve train problem on mine.

 

[At1Maverick]

So,just an update. I replaced the distributor and seems like the problem is gone, no pinging and the surge/hesitation is gone, idles much better too.

 

[GT Rob]

What kind of dizzy did you use. And did your car back fire mine dose

 

[the5.ohh]

I had the same issue guys. Turned out to be a leaking O-Ring on an injector, so check your injectors. Also if your O2 sensors are OG, replace them.

 

[At1Maverick]

GT Rob, mine didn't backfire, but there was a significant loss of power when it started acting up.