Car running like *****, wild codes.... please diagnose

[Moco]

Gents,

My car (with mods below) is running absolutely disgustingly. It bucks so hard in every gear, that you run the risk of breaking your neck. Its about undrivable on the street and it bucks on the highway as well. If I roll out of a stop and press the gas harder than just a hair, the car will buck and jerk like wild. The only way it can be driven right now is if I slowly accelerate to road speed. It idles, pretty well though at about 800 rpm or so. Well obviously the check engine light came on and popped the following codes. Now keep in mind, that the rear 02 sensors were replaced about a few weeks ago....

P0171
P0174
P0141
P0320!!!???

I have a BBK hi-flo H-pipe that has been beat to hell and the cats are probably damaged, but I figured replacing the 02 seonsors should have took care of the P0141. Does anyone have any suggestion as to what problem/problems I have with this car? Im especially puzzled by the P0320 code - what usually causes that?

Thanks,

 

[tomustang]

P0171 System Too Lean - Bank No. 1.
P0174 System Too Lean - Bank No. 2.
P0141 Downstream Heated Oxygen Sensor Heater circuit fault - Bank No. 1.
P0320 Ignition Engine Speed (PIP) Input circuit fault.

A Coil on Plug engine that cranks but fails to start, in many cases, will often have a problem in the crankshaft position sensor circuit (code P0320). Loss of the camshaft position sensor signal (code P0340) may prevent the PCM from properly synchronizing the fuel injectors, but may still allow the engine to start and run in a limp-in mode

Diagnostic Trouble Code (DTC) Descriptions

DTC

Description

Possible Causes

Diagnostic Aides

P0320 - Ignition Engine Speed Input Circuit Malfunction

The ignition engine speed sensor input signal to PCM is continuously monitored. The test fails when the signal indicates that two successive erratic profile ignition pickup (PIP) pulses have occurred.

- Possible Causes

* Loose wires/connectors.
* Arcing secondary ignition components (coil, wires and plugs)
* On board transmitter (2-way radio)

The DTC indicates that two successive erratic PIP pulses occurred.

 

[Seraphitia102]

does the trouble codes actually come up if you're running too lean on air/fuel ratio?

 

[jstreet0204]

First make sure you are getting fuel. Possibly a clogged fuel filter. The bucking bucking could be caused by lack of fuel, which in turn could cause the irratic crank sensor reading. Or it could be the other way around with a bad crank sensor not being able to time the fuel right, so if you know you are getting enough fuel check the crank position sensor. Good luck with it...

 

[Moco]

Thanks guys,

Will check the crank position sensor. Ill let you guys know once I fix this thing.

 

[KronicRacer]

first things first fuel filter. and reset the computer..... if that doenst work keep us posted

 

[jstreet0204]

first things first fuel filter. and reset the computer..... if that doenst work keep us posted

Exactly, always check the cheapest fixes first. It will save you money in the long run when chasing down problems like this.

 

[Moco]

Alright Guys,

Some of these things Ive never done before, I hate to sound stupid but will someone give me an idea of how to determine if my fuel filter is bad? what do I look for, what do i test? Second, my crank position sensor seems like its has the proper clearance from the timing wheel and it looks like the connections are proper, how do I specifically check the sensor to make sure its working. finally, should I assume that my mangled cats on the h-pipe are not the cause of this problem?

thanks for all your help.

 

[jstreet0204]

I'd just go ahead and replace the fuel filter. Probably needs to be changed anyway. When you say the cats are mangled, what do you mean. Is one of them of them crushed or anything to the point where it may be causing a restriction?

 

[Moco]

Alright, fuel filter is at th etop of the list.

Jstreet:

The cats are not really crushed, but due to the low height of my car, they have been getting raked over speed bumps and such for almost 3 years now and they recently lost this outer metal shell to them. So I dont know if thats a critical part or not - but I dont think bad cats would necessarily cause my car to run like it is.

Also, would a bad fuel filter cause my car to leak fuel? Cause today, I went to the gas station and after about filling up 3/4 of the way, I noticed a stream of fuel dripping from the back - at approximately the area the fuel filter would be. How complexe a job is the fuel filter change, I mean is this a quick thing that can be done in one afternoon or are there lots of hard to get to areas that necessitate removal of other components?

 

[d98gt]

Changing the fuel filter only takes a few minutes.

Goto an autostore and buy the tool needed (shouldn't be any higher than $5 or so).

 

[Moco]

Roger that. Thank you guys for all the replies. I will try to hit up the fuel filter this weekend. If that doesnt work, then may be Ill do a tune up with some fresh plugs. If still problems exist then I'll go ahead & replace the h-pipe and 02's.

Thanks for all the replies.

 

[Moco]

UPDATE:

Ok, so I got around to doing some stuff on my car this weekend. First off, replaced the fuel filter as it was the simplest step. This appeared to help the matter some but not relieve the problem - the car would still buck but not as violently and it was in drivable condition. next, addressing the P0320 code, I inspected and removed my crank position sensor and reinstalled it. The car felt more stable and drivable after this and the P0320 code has not come back in about 50 miles of driving. Finally, I took the car to my exhaust guy and he welded in two new cats, and fixed a couple of major exhaust leaks. He told me that my drivers side header (FMS shorties) needed a new gasket - so I still have some what of a leak but not the mostrous leak as before.

Anyway, the car feels MUCH better with almost no bucking at all so far. Only thing I did notice was that when I got on it in second gear, around 4500 RPM, the motor bucked as if it hit the rev limiter. This only happened in 2nd gear. Anyone know what could be causing this?

Regardless, of the 2nd gear issue, the car feels MUCH better to drive and hopefully the header gasket can be fixed soon as well.

 

[Moco]

UPDATE II

Ok, so I drove the car around for a little bit more and have some bad news to report. The bucking is still present, but only when I get on the car. For regular driving the car feels terrific, just like new, but if I were to hammer it the car would start to buck (or miss? it feels like its hitting the rev limiter) around 4500 rpm. Like i said for normal driving it feels fine, but I really want be able to hammer the gas and have fun every once in a while. I got a P0141 code right after I left the shop today, but it was not causing a Check Engine Light. No other codes were present. Currently my scanner returns a PASS with no codes popping up, but the car still bucks. I dont think the P0141 (02 sensor heater circuit) would be causing the bucking. Would a big exhaust leak from the destroyed drivers side header gasket cause bucking? Anyone have any other ideas?

 

[KronicRacer]

did you reset the computer after all these fixes?

 

[Moco]

Yes, i disconnected the battery for a good 30 min. The thing with the bucking is that it only starts when the car is warmed up. Like for example, this morning I thrashed the car for about 10 miles and it ran fine, both under normal acceleration and WOT. HOWEVER, after the motor warmed up then the bucking started. Does that help narrow it down at all? Im still not getting a CEL though.