Engine still running rough

[caw333]

Thought I had my problem fixed cause I had some plugs arching but I'm still having problems. Heres what I got on a friends scanner.
PO102 MAF or VAF circuit low input.
PO103 MAF or VAF circuit high input.
PO339 Crankshaft position sensor A CKT Intermittent.
PO341 Camshaft position sensor A Bank 1 CKT range / Perf.
The codes 339 & 341 show to be pending codes.
My questions are could they all be bad or could they be linked to just 1 sensor and throwing the others off. The engine is running rough and smells rich. It sounds like its not hitting on all cylinders. After running engine for a min. the exhaust manifold on # 2 & 7 cylinder is just warm and all others are hot.The engine is a 1998 vortec 350. The truck is a 4wd tahoe.

[maxwedge]

Certainly have a maf issue with those 2 codes, disconnected, dirty or just bad, I'd tackle that first.

[j cAT]

remove all plugs see if all look the same. that will eliminate that area. remove ckt and check wires/connector/resistance/build up of debris on tip.if resistance too high should read 2-3000ohms replace its only 30-50.00dollars. maf disconnect connector see if it changes operation of engine better or worse .if better maf is bad. you must check for vacuum leaks as this is common on vehicles this old..........what caused problem with plugs/wires that you mentioned ?

[maxwedge]

If this was a plug or wire issue, it would set a misfire code, the symptoms and code do not point to a plug or wire . 341 can also point to the cam and crank sensor out of synch and must be set with a full function scanner. The pcm will use a default setting for the maf with those codes which will cause a lean condition under power. Correct on looking for vacuum leaks, but of course this would also set a lean code.

[caw333]

Thanks for the info. Friday when I'm off work I'll start by replacing the maf sensor and hope for the best. When you unplug a maf sensor what does the engine start doing. I guess I could find someone with a truck around my year and see what happens. I just hate to start buying a bunch of expensive sensors.