98 GTP service engine light and slight hesitation?

**Cobraeater** · 02-04-2012

So tonight I was past by a truck that was easily doing 100 and I thought I would show him up so I speed up caught up an went to past when the car felt like the boost was pulsating. The service engine light started flashing and stayed on. Now I took and had the car scanned at advance and I got no specific code just said emissions. Car has 94k miles zzp 3.5 pulley cold air and straight pipe exhaust unknown is exactly how I bought it. I'm good with mechanics I've just never worked with the 3.8 before. Would like to hear what you guys think? Cat? Plugs wires? misfire? Most people claiming this flashing ses light say misfire but not throwing that code.

**Scottydoggs** · 02-04-2012

if your cel is on you have a code in there, address it first, and try a tune up .

flashing cel means something catastrophic is going on, misfires, cat, and so on.

**Cobraeater** · 02-04-2012

Ok I did get it scanned and all the scanner said was emissions no code nothing. I was told to take it to a shop and pay 75 to find out what it is but. I thanks that's a waste of my money. Like you said there be a code but there wasn't..guess I'll go get plugs and wires..it just didn't fell like a miss I've had plenty of cars that missed before such as the dreaded LT1 opti spark and a icm and plugs and wires I'm just hoping someone might have a clue would a clogged cat cause this?

**Cobraeater** · 02-04-2012

Maybe O2 sensors?

**Iceman6669** · 02-04-2012

Flashing CEL means multi misfires... What kinda plugs and wires are you running??? ZZP wires have been known to cause a misfire at high speeds...(not saying you have ZZP wires just an example.)

**Iceman6669** · 02-04-2012

Also you didn't mention year of your car.. Also are you running headers? Or how about what kinda tune do you Have??

**Cobraeater** · 02-04-2012

It has stock plugs and wires. No headers all exhaust stock besides cat back. And the year is in my title

its a 98. So I took it to autozone to get it scanned I figured I would try a different place and same thing! Just says emissions...no misfire code :/

**Cobraeater** · 02-04-2012

And not sure on the tune stock I'm guessing? I hate buying a car blind

**chevyy1212** · 02-04-2012

Have you ran a fuel injector cleaner through recently. I ran Lucus through mine and fouled a plug did the same thing. Only when I got on it.

**GTPSHAWTY** · 02-04-2012

im going thru the same thing with my 98.. only difference it only sputters when boost starts coming.. other than that its fine... i read up on past threads and they always seem to die before the solution is found.. (new plugs and wires new coil packs).... codes where egr valve recirrclatin in valve 2 and random misfires..

**Scottydoggs** · 02-04-2012

whats the emissions code you are getting, that may be your problem. always fix a known issue first, it could be a bad cat or something.

a scanner wont just say emissions, a code will come up.

**Cobraeater** · 02-04-2012

Ya it's same thing here and trust me when I find the solution I'll post it lol cuz I have the same problem with unanswered questions. And no I haven't ran injector cleaner through it. And The same problem it starts to hesitate only when boosting...

**Cobraeater** · 02-04-2012

Well see that's just it. The guy at the auroparts store said its just coming up emissions no specific code...I guess there scanners cant identify it? Don't get me wrong I know your right...there should be a code

**GTPSHAWTY** · 02-04-2012

dats weird.. mine kept showin p0300 and i cant think of the number but it says egr valve 2

**Scottydoggs** · 02-04-2012

get under your car and bang on the cat and listen for stuff rattling around in there, if so you need a new cat. you can use the palm of your hand to hit it, when its cold of course. free test anyways if its not that, but a bad cat can also make the cel flash.

**Cobraeater** · 02-04-2012

Ok I'll go give that a try now

**GTPSHAWTY** · 02-04-2012

i just did it to mine... no rattle... sounded hallow...

**Cobraeater** · 02-04-2012

Ok so I had the chance to put the car on my shops scan tool and sure enough code P0304 came up misfire in number 4. So soon as I get my paycheck I'll get coils plug and wires. Scan tool also said it could be a vacuum leak an injector fault or low/high fuel pressure. If you guys have any suggestions let me know.