My car is chugging all the time. I have no idea what's wrong with it. No codes come up. I just had the opti replaced. I had new plugs put in, new fuel filter, pcv valve. It still has not helped. I had the fuel system cleaned. This helped some, for about 3 weeks then the problem returned. I thought it was the opti. I had it replaced. The problem is still there. If anyone has any ideas I'de greatly appreciate it.

I had the fuel pressure tested as well. It was good.
I think I'm going to have it check out again.

It came outta the shop today. Ran fine for about 20 minutes. Then started acting up again. One another note ever since it started doing this my fuel economy has been TERRIBLE. Terrible would be an improvement actually

 

fuel pump

 

Pull the vac hose off the fuel pressure regulator after the car has been running and shut down. See if it is wet or pull a vacuum on the regulator with a hand pump. If it's wet or the regulator won't hold a vacuum, then the diaphragm has a hole in it. Replace it since it is allowing the fuel to enter the vac line and feed back into the intake manifold causing a rich condition and bad fuel economy.

If that doesn't do anything, try a fuel pressure gage with a hose and tape it to the windshield so you can see it when your driving. The pressure should not drop below about 40 to 42 psi.

 

I've had the following replaced/
Opti.
Plugs
Wires
Fuel Filter.
MAP Sensor
O2 Sensors.
PCV Valve...

I recently changed the plug wires are finding out #5 wire was dead. This helped a little bit. Now I have a random miss. I'm thinking it's the plugs. Because, the service shop put in Bosch plugs.
. I think they're prolly shot
What do you guys think?

 

this could be ur fuel pump startin to take a ****. You also gotta make sure that all the wires are connected good, cause they might feel as if they are fully on, but not be. Did u change out the coil?? that could also be the problem. So this usually does it when it's hot then, right?? Like stated above, it could be ur diaphragm startin to take a **** too. There could be a lot of things wrong. How's the temperature?? how's the idle? Does your car get hot or does it stay at normal temperature. There might also be a chance of maybe a blown head gasket, or worn rings, but that would give you more problems. Tell us al the problems it has and we'll be able to help you more.

Cisco

 

I got a fuel pressure test done a while back, it's fine. I got a new wires, coil tonite. I haven't putthe coil in though. How do I check the diaphragm?

After Wire Change
1. At idle. It seems to run smooth then there's a random miss. Then, idles smooth and so on.
2. Driving from 5-40 it seems to have an irratic miss. It surges then smoothes out. It's more noticables at this point than idle.
3. Pressing down to accelerate the missing gets worse.
4. 45-60 there is a definite miss. It rocks the car when it misses.

I put a new coil in tonight. No change. Come to think if it all this started when I lost my turn signals. I wonder if it's related in anyway? Whenever I disconnected the negative terminal, the headlight motors kicked on. Again, electrical related?

It seemed to run pretty good this morning, until it started getting warm then the miss became more noticeable could it be the optical sensor heating up and possibly malfuntioning? I don't have any codes a mal funtioning sensor would throw a code 16. I'm thinking maybe TPS too. I've noticed when it's cold in the morning the car no longer will have a high idle then idle down like it used to. IAC motor or TPS?


I noticed something this morning. It seems that all the wires came out of the harness and they're all touching. Could they be arcing and causing this misfire?

 

Today I got my wires changed out. Although the majority of the miss is gone. It's still there. The list of parts replaced continues to grow. I'm beginning to think I have a serious issue on my hands.

Parts Replaced:
ECM - 3 Times.
Injectors.
O2 Sensors
Opti - 1 week old.
Wires - 1 day old.
Plugs - Under 1k miles pulled and look new.
PCV Valve.
Fuel Filter.
ICM.
MAP Sensor.

I really hope it's not my fuel pump going out. Although my problems start when the car is warm. Something is breaking down and causing my missfire. Any ideas?

 

why dont you just change the fuel pump for the heck of it it might just be that.

just a thought.
good luck

 

I just got off the phone when the shop. They are going to run some tests on it tomorrow.

 

it might be your injectors...they way you described your problem it sounds like my old 91 camaro...the studdering that goes away and comes back...try those...

 

whoops, you said they were replaced now i agree with cridom, go for the pump.