Q: rough idle and dies when you give it gas it either revs up and hiccups or just dies

asked by on October 29, 2016

i have an 89 f150 xlt lariat 5.0 efi. we were having some problems with it starting and backfiring and we suspected timing was the problem. we put new timing chain in it did everything perfect. fired up for about 4-5 mins died wouldnt start again new plugs wires coil pack starter fuel pump and fuel regulator. still didnt want to start back up. we checked the firing order and how the pumps were ran and they were all ran fine. put in new distributor got everything lined up perfect. started and idles but idle was rough and when you hit the gas it will either rev up but hiccups and sputters and backfires sometimes. flashed my codes got map sensor tps sensor and idle air valve. replaced map and tps cleaned idle air valve. still doing the same thing. all codes are gone. also tested the injector pluse was fine.

all new-plugs,wires,full distributor,coil pack,starter,fuel pump,fuel filter,fuel regulator,timing chain set,temps sensor tps,cleaned idle air valve,map
My car has a manual transmission.

Hi there. I would start with a compression test. It is common for there to be a valve issue with one or multiple valves with bad seats which will cause this. If it passes the compression test then the timing needs to be checked with a timing light to see how it is moving when the engine is revved. I have had computers fail on this truck and end up adjusting the timing in the wrong direction. If you are looking to have this timing issue checked, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose why it is backfiring.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Loud clunking when shifting reverse. Is it the pressure switch?

Hello. It sounds like you either have a mount that is failing or you may have an issue with the valve body in the transmission. I have also seen the driveshaft make this noise where it enters the transmission. It...

How do I engage the alarm system?

The alarm system on your vehicle was designed to keep your vehicle safe and prevent theft. There are several different methods are arming and disarming the alarm system. To engage the alarm system. Turn the vehicle off, on auto...

Fuel pump engages. Batery good, alternator good volts, jump start helps when wont start. Temp does not matter. Intermittent?

Hello. Thank you for writing in. There are several reasons your vehicle may only start when jump starting. The first and most common is a build up of resistance that is causing you to need a boost of voltage to...

Related articles

The Top 5 Selling Cars in Connecticut in 2012
Connecticut Connecticut offers plenty of rain and its fair share of snow during the winter months, which means drivers need vehicles that can handle these conditions. Top selling vehicles in previous years have included the Toyota Camry, Corolla and the...
The Best Used Cars to Buy If You're an Undercover Cop
If If you're an undercover cop, when you choose a used vehicle, your main purpose is to look like anything but a cop. That means, of course, that an unmarked Crown Victoria is probably not the wisest choice. We’ve...
2012 Ford Fusion vs. 2012 Toyota Camry: Which Should I Buy?
While most people believe that domestic sedans just cannot compete with the Honda Accord and the Toyota Camry, the industry leaders, that is not necessarily true. Yes, there are some metrics where the Camry just excels, however the Ford Fusion...