I have a 91 bonneville with a series 1 3.8..... It will crank right up, runs smooth for a second or 2 then misfire at random, as you accelerate, it will get worse. It just jumps back and forth from running smooth to running rough and miss fires. I pulled the codes and there was a crankshaft pos code. So i replaced that and nothing, same thing. I have even replaced the PCM, CMP sensor, ignition module, MAF sensor, ignition coils, The complete harness for the ignition module, plugs, wires ect. Any help would be great....

Hi, my mother has a 94 Regal with the same engine and it started to hesitate and run rough on acceleration. This usually happens from medium to heavy acceleration. When I looked in the rad, there is oil mixed with the coolant and there is a coolant leak somewhere - I think below the plenum but not sure. I believe, from what I have read that the LIM gasket needs to be replaced. A mechanic, not a very good one, replaced wires and plugs but the problem is still there so I think it's LIM gasket. Do you have oil in the coolant also?

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poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

First off, to the OP, did it have an engine swap or is it the original engine which would be the VIN C 3800?

96 SSEi, if this has the original engine, it does not have a LIM or UIM, it just has an intake manifold.

First thing we would need is for you to pull the codes and report them back here

http://www.pontiacbonnevilleclub.com/forum/viewtopic.php?f=51&t=8689

http://www.pontiacbonnevilleclub.com/forum/viewtopic.php?f=51&t=1624

Did the new crank sensor make the SES light turn off, or is it still on for the sensor?

Also check fuel pressure.

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The Fleet:
'93 SSEi - Twincharged + manual Build thread
'97 Camaro - Top swap
'05 STS - V8, AWD, her DD
'92 Trofeo - Fair weather DD
'99 Montana - top swap 3800
'04 Sierra 2500HD - LLY Duramax

Current project:
Something cool, trust me.

Upcoming projects:
'92 Bonneville SSE
'87 LeSabre T-type
'67 LeSabre

Gone to greener pastures:
'84 Sierra Classic - Twin turbo 3800
'97 LeSabre - Top swap

RIP:
'86 LeSabre - pictures
'93 SE - L67

It does not have a lower intake manifold or a upper. It has a single manifold> There is not coolant in the engine oil or visa versa. Fuel pressure is okay....38psi-46psi......And i have not looked at the car in so long that i dont know if the CKP code is still there. Battery is dead so im pretty sure the PCM has reset.

I would venture to guess that the code is still there. When it acts up which it always does hot or cold, after a little while it will come on. Like i said i have been so pissed at it for the longest i have not touched it.

Ill get the codes